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Regional Report: 1990 Travel Behavior Inventory Summary Report
June 1994 1990 Travel Behavior Inventory Summary Report Twin Cities Metropolitan Area Click HERE for graphic. Contributing Organizations: Metropolitan Council, Transportation Advisory Board, Regional Transit Board, and Minnesota Department of Transportation Metropolitan Council Mears Park Centre 230 East Fifth Street St. Paul, Minnesota 55101-1634 612 291-6359 TDD 291-0904 Metro Information Line 229-3780 Travel Behavior Metropolitan Council Members Dottie Rietow, chair Roger Scherer David Hartley Bill Schreiber Patrick Leung Mary H. Smith Esther Newcome Julius Smith E. Craig Morris Sondra Simonson Dede Wolfson Martha Head Stephen Wellington, Jr. Barbara Butts Williams Kevin Howe Carol Kummer Terrence Flower 1990 Travel Behavior Inventory Summary Report Writers: Stephen Alderson, Mark Fillipi, Bill Barrett Editors: Pat Ferguson Hanson, Jeanne Landkamer, David Hennessey Design: Clifton W. Bums Jr. 1990 Travel Behavior Inventory Twin Cities Metro Area Summary Report CONTENTS Page Executive Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . .v Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1 Study Purpose and Overview. . . . . . . . . . . . . . . . . . . . .1 Organization of the Summary Report. . . . . . . . . . . . . . . . .1 Chapter 1 The Region -- 1970 to 1990 . . . . . . . . . . . . . . . . . .3 Growth. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .3 Dispersal . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4 lifestyle . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7 Chapter 2 Regional Travel. . . . . . . . . . . . . . . . . . . . . . . .9 The Average Travel Day. . . . . . . . . . . . . . . . . . . . . . .9 Through and External Travel . . . . . . . . . . . . . . . . . . . 12 Where People Travel - Origins and Destinations. . . . . . . . . . 14 How People Travel - Modes . . . . . . . . . . . . . . . . . . . . 15 Demographics and Travel . . . . . . . . . . . . . . . . . . . . . 17 The Role of Transit . . . . . . . . . . . . . . . . . . . . . . . 23 The Role of the Auto. . . . . . . . . . . . . . . . . . . . . . . 26 Auto Occupancy. . . . . . . . . . . . . . . . . . . . . . . . . . 31 Peak-period Travel. . . . . . . . . . . . . . . . . . . . . . . . 36 Highway Speeds. . . . . . . . . . . . . . . . . . . . . . . . . . 40 Chapter 3 Travel and land Use. . . . . . . . . . . . . . . . . . . . . 41 Central City, Suburbs and Rural Areas . . . . . . . . . . . . . . 41 The Central Business Districts. . . . . . . . . . . . . . . . . . 46 University of Minnesota . . . . . . . . . . . . . . . . . . . . . 53 Minneapolis-St Paul International Airport . . . . . . . . . . . . 54 Chapter 4 Major Findings . . . . . . . . . . . . . . . . . . . . . . . 57 Trip Rates. . . . . . . . . . . . . . . . . . . . . . . . . . . . 57 Driving Alone . . . . . . . . . . . . . . . . . . . . . . . . . . 60 Travel Time and Distance. . . . . . . . . . . . . . . . . . . . . 60 The Future of Mobility. . . . . . . . . . . . . . . . . . . . . . 62 Appendices . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 A-Acknowledgements. . . . . . . . . . . . . . . . . . . . . . . . 65 B-Revised Zones and Networks. . . . . . . . . . . . . . . . . . . 66 Travel Behavior List of Tables Table. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1. Comparative Profile: Public Transit and Auto Travel . . . . . . . . 16 2. Person Trips by Travel Mode and Purpose. . . . . . . . . . . . . . 17 3. Regional Average Trip in Minutes . . . . . . . . . . . . . . . . . 22 4. Regional Average Trip in Miles . . . . . . . . . . . . . . . . . . 22 5. Household Characteristics by Autos Owned . . . . . . . . . . . . . 26 6. Number of Households Classified by Auto Ownership. . . . . . . . . 29 7. Auto Occupancy by Trip Purpose . . . . . . . . . . . . . . . . . . 31 8. Regional Trip Time and Distance Compared to CBDs . . . . . . . . . 32 9. Comparative Profile: "Peak-Period" Travel vs. "Off-Peak' Travel. . 37 10. Summary of Highway Speed Study Findings in Miles Per Hour. . . . . 40 11. Households, Cars, and jobs by Development Framework Areas. . . . . 42 12. Number of Trips by Development Framework Areas . . . . . . . . . . 44 13. Travel Purpose by Development Framework Areas. . . . . . . . . . . 44 14. Auto Driver Travel Time and Distance by Development Framework Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 15. Transit Rider Travel Time and Distance by Development Framework Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 16. Central Business Districts Change in Population and Employment . . 46 17. Total Daily Arrivals in Both Central Business Districts. . . . . . 47 18. Central Business District Person Trips - Average Weekday Arrivals. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 19. Comparative Profile Central Business Districts . . . . . . . . . . 48 20. Average Weekday Airport Traffic. . . . . . . . . . . . . . . . . . 55 21. Arriving Travelers' Destination by City. . . . . . . . . . . . . . 56 22. Trip Rates and Household Characteristics . . . . . . . . . . . . . 58 23. Historic Trip Rate Comparisons by Household Size . . . . . . . . . 59 24. Number of Trips by Mode and Purpose. . . . . . . . . . . . . . . . 60 List of Figures Figure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1. Percent Regional Change 1970 to 1990. . . . . . . . . . . . . . . . .4 2. Employed Labor Force by Gender . . . . . . . . . . . . . . . . . . .7 3. Licensed Drivers 1970-1990 . . . . . . . . . . . . . . . . . . . . .8 4. Number of Person-Trips by Time of Day. . . . . . . . . . . . . . . 10 5. Purpose of Travel by Time of Day . . . . . . . . . . . . . . . . . 11 6. Total Trips by Purpose of Travel by Time of Day. . . . . . . . . . 11 7. Composition of Through Travel. . . . . . . . . . . . . . . . . . . 12 8. Origins and Destinations of All Trips. . . . . . . . . . . . . . . 14 9. Choice of Mode: All Trips and Work Trips . . . . . . . . . . . . . 15 10. Daily Travel Rates-Mates . . . . . . . . . . . . . . . . . . . . . 18 11. Daily Travel Rates-Females . . . . . . . . . . . . . . . . . . . . 18 12. Daily Travel Mode-Males. . . . . . . . . . . . . . . . . . . . . . 19 13. Daily Travel Mode-Females. . . . . . . . . . . . . . . . . . . . . 19 14. Percent of All Person-Trips by Car Ownership . . . . . . . . . . . 21 15. Percent of Transit Trips by Car Ownership. . . . . . . . . . . . . 21 Summary Report 16. Bus Trips by Household Income . . . . . . . . . . . . . . . . . . 24 17. Distribution of Regional Public Transit Trips - 1990. . . . . . . 25 18. Average Number of Vehicles by Household Income. . . . . . . . . . 29 19. Trips per Household by Income . . . . . . . . . . . . . . . . . . 30 20. Trip Duration by Income . . . . . . . . . . . . . . . . . . . . . 30 21. Trip Length by Income . . . . . . . . . . . . . . . . . . . . . . 30 22. Average Auto Driver Trip Time . . . . . . . . . . . . . . . . . . 35 23. Percent of Passenger Car Trips by Time of Day . . . . . . . . . . 36 24. Average Person Trip Starts and Trips in Motion. . . . . . . . . . 37 25. Split of Work-Oriented vs. Non-Work-Oriented Trips . . . . . . . 38 26. Number of Person Trips by Time of Day . . . . . . . . . . . . . . 38 27. Profiles of Arrivals at Selected Major Generators . . . . . . . . 39 28. Average Freeway Speeds Twin Cities Metro Area, Fall 1990. . . . . 40 29. Commuting Origins and Destinations. . . . . . . . . . . . . . . . 43 30. Average Daily Central Business District Arrivals per Regional Resident. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 31. Morning Rush in St Paul Central Business District . . . . . . . . 49 32. Morning Rush in Minneapolis Central Business District . . . . . . 50 33. University of Minnesota Person Trips for a Ten-Hour Period. . . . 53 34. University of Minnesota Person Trips by Mode, Ten-Hour Period . . 54 35. Minneapolis-St. Paul International Airport Daily Traffic Volumes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 36. Per Capita Trip Rate - Metropolitan Area. . . . . . . . . . . . . 58 37. Mode of All Trips and Work Trips. . . . . . . . . . . . . . . . . 61 38. Trip Distance and Time. . . . . . . . . . . . . . . . . . . . . . 62 39. Trip Multiplication Effect. . . . . . . . . . . . . . . . . . . . 63 List of Maps Map. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Page 1. Increase of Households . . . . . . . . . . . . . . . . . . . . . . .5 2. Increase of Jobs . . . . . . . . . . . . . . . . . . . . . . . . . .6 3. External Traffic Volumes . . . . . . . . . . . . . . . . . . . . . 13 4. Autos per Person . . . . . . . . . . . . . . . . . . . . . . . . . 20 5. Area Served by Public Transit. . . . . . . . . . . . . . . . . . . 23 6. Percent of Households with No Car. . . . . . . . . . . . . . . . . 27 7. Autos per Household. . . . . . . . . . . . . . . . . . . . . . . . 28 8. Average Trip Distance for All Trips. . . . . . . . . . . . . . . . 33 9. Average Trip Time for All Trips. . . . . . . . . . . . . . . . . . 34 10. Percent of Total Trips Bound to Minneapolis. . . . . . . . . . . . 51 11. Percent of Total Trips Bound to Saint Paul . . . . . . . . . . . . 52 Summery Report EXECUTIVE SUMMARY Daily travel, the ability to get where we need be, is important to all of us. This report is about daily travel in the Twin Cities metropolitan area as revealed in a major 1990 study. "The daily rat race is picking up,' proclaimed one early news report on the study. Indeed, total traffic in the region took a significant jump in the 20 years since a similar travel behavior study was last done in 1970. Population, and the number of households, jobs, workers and licensed drivers were all increasing during that time. An expanding urban region with a highly mobile populace creates a dynamic new picture of daily travel. Consider some of these significant findings: - The car has become "king." The number of two-car households has doubled since 1970. The preferred way to travel within the region is dearly driving alone, accounting for almost half of all trips and over 80 percent of all work-related travel. - Today the typical area resident is making more and longer trips than 20 years ago. The average traveler now spends one and a half hours per day traveling in the region, makes 5 trips and covers 32 miles. The average distance traveled to work -is 9 miles and takes 20 minutes. - The importance of public transit to the region's residents is somewhat hidden in the overall travel statistics. Although buses moved only 2.5 percent of all trips and 5.5 percent of all work trips, bus trips were reported by 10 percent of all households, representing 1 in 20 people in the region. Within the lowest quartile of households by income, nearly one in five used transit. Jobs, homes and travel have moved to the suburbs. - In 1970, 54 percent of the region's households were outside Minneapolis/St. Paul; by 1990, the number was 69 percent - In 1970, 44 percent of the region's jobs were outside Minneapolis/St. Paul; by 1990, the number was 63 percent. v Travel Behavior - Commuters no longer travel inward in the morning and outward at night instead, they commute throughout the region, with suburb-to suburb commuting outweighing suburb-to-city. Lifestyle change has greatly influenced travel in the Twin Cities area. - Nearly seven of every ten women over age 16 were in the work force in 1990. - There were 600,000 more licensed drivers in 1990 than in 1970; the number of licensed women drivers now equals licensed men drivers. - The number of people ages 65 years and older with licenses increased from 66 percent in 1970 to 84 percent in 1990. - A majority of households now have two cars; 33 percent had two cars in 1970 and 65 percent had two cars in 1990. - Households without cars fell to under 1 0 percent of all households and represented only five percent of the population, meaning 95 out of every 100 persons is in a household with a car. The afternoon "rush hour" is not dominated by work-oriented travel. Shopping trips and other service-related travel constitute a significant proportion of late afternoon trips. This trend reflects the needs of two-worker households. Many destinations- like day-care pickups and grocery shopping-are stops on the way home from work and reflect the way that busy people cope with the time demands of contemporary society. Societal change, plus growth and dispersal of the region's population and work force, have been accompanied by an explosion in travel in the past 20 years. The greatest change of all has occurred in vehicle-miles traveled, which best measures the demand for highway capacity. The region's population grew by 20 percent from 1970 to 1990, but daily vehicle-miles - traveled increased by 130 percent Four factors are at work multiplying travel. The combined influence of these four factors added up to an increase in daily travel of over 32 million vehicle miles: - Population growth added 8 million miles of daily vehicle travel. - Higher per-capita rates of personal travel added 9 million miles of daily vehicle travel. In large part this is due to more workers going to more jobs. - Switching from a car pool or bus to driving alone (decline in auto occupancy) added 5 million miles of daily vehicle travel. - Longer trips caused by the spread of development added another 10 million miles of daily vehicle travel. Traffic is a highly complex response to urban expansion, new societal norms and the need to access millions of individual destinations. Personal mobility has become paramount The region's population is expected to increase to 2.7 million by the year 2010; nearly all of this growth is predicted for the suburbs. If increased trip distances follow the new suburban and exurban growth as in the past, it may fuel a continued explosion of vehicle-miles traveled. vi INTRODUCTION Study Purpose and Overview The 1990 Travel Behavior Inventory (TBI) is a comprehensive travel survey of the Minneapolis-St. Paul metropolitan area and the first available since 1970. The TBI documents when, why and how Twin Cities residents and businesses use the region's highways and public transit. This data has been used to refine and update the region's computerized travel forecasting models and provides a factual basis for decisions about highway and transit improvements. The Metropolitan Council, Minnesota Department of Transportation, Regional Transit Board and Transportation Advisory Board were the lead agencies for the TBI and principal users of the study. Collecting travel information in 1990 allowed for coordination with the demographic data base of the 1990 census. The TBI used several coordinated surveys to gain a comprehensive overview of travel by vehicles. Travel surveys were conducted over a period of nine months, during May to December 1990. The Home Interview Survey was the centerpiece of the TBI; almost 10,000 randomly selected households kept a travel diary for one day. In addition to the Home Interview Survey, employees and visitors at 250 work places provided information on their commute to and from work, 9,000 drivers entering the metropolitan area at 30 selected locations answered questions about their trips; and 24,000 bus riders responded to on-board surveys of their transit use. Data was also collected at special locations downtown Minneapolis and St. Paul, the University of Minnesota, the airport and two shopping centers. In addition to the travel surveys, the TBI recorded data on economic activity and development using an inventory of third quarter 1990 employment, and aerial photos flown in April. Finally, the study updated travel geographic units (Traffic Assignment Zones), and associated highway and transit networks. The final products of the TBI are the revised travel forecast models. These include models for predicting future travel by purpose, time of day, travel mode and travel route. The TBI data and forecasting procedures provide the region with federally required planning and research tools to apply to transportation problems and issues in the 1990s. Organization of the Summary Report As the region has grown and changed, so have the means and methods of travel. A summary of the major changes in the region is provided in Chapter 1. Regional travel behavior 1 Travel Behavior has been studied since 1949. Throughout the report this historical background is used. A perspective on travel change is critical to preparing policy for the future. Chapters 2 and 3 provide an overview of major findings regarding 1990 daily travel in the region. Drawn primarily from the findings of the Home Interview Survey, the picture of daily travel is supplemented with findings from the other travel surveys. The year 1990 is significant because it marks a point at which interstate construction was finished in the region (with the exception of a few miles of I-394). From this decade forward we will primarily use the "in-place" transportation network. Because traffic is channeled to the main transportation arteries, 1990 travel patterns will persist and intensify. Chapter 4 concludes with a review of the major trends revealed in the data surveys of the 1990 TBI. Click HERE for graphic. 1. THE REGION-1970 TO 1990 The Twin Cities metropolitan area includes the counties of Anoka, Carver, Dakota, Hennepin, Ramsey, Scom and Washington. In 1990, these seven counties had a total population of 2,288,721 living in 875,504 households. The number of working residents totaled 1,243,637; the unemployment rate was 4.6 percent. The Twin Cities area was sixteenth largest in 1990 population among the nation's 25 largest metropolitan statistical areas. Between 1980 and 1990, its rate of growth ranked twelfth. In 1990, the region's average household size was 2.56, compared to 2.63 nationally. Increased personal mobility has been a hallmark of the last two decades. Region-wide daily vehicle miles of travel increased 130 percent, while population grew by only 20 percent Three major demographic forces lie behind travel growth in the region. They are: population and household growth, the dispersal of housing and jobs outward in the region, and lifestyle changes. The Twin Cities' households and work force increased more than population. The post-war movement of households to the suburbs continued and became reinforced as job growth shifted from the central cities to the suburbs. These changes resulted in more people making more and longer trips, primarily by automobile. Growth The average metro resident spends one to one and one-half hours each day traveling in a vehicle of some type. Daily trips may be to work, a movie, or anything in between, be it as mundane as grocery shopping or as critical as an emergency hospital run. A trip made reflects someone following their interests or meeting their needs. Increase in travel is a barometer of economic strength, because travel takes time and money. As the region grows, so does travel, although there is not a simple one-t"ne relationship with population, as is discussed in the data that follows., In the past two decades: - The region's population grew from 1.875 million in 1970, to 2.289 million in 1990 (a 22 percent increase). - The number of households grew from 574,000 in 1970, to 876,000 in 1990 (a 53 percent increase). However, the average household size fell from 3.3 to 2.56 during the same time period. - The age group responsible for most of the travel-those aged 18 to 6 by 43 percent between 1970 and 1990. These demographic changes were reflected in increased travel. Work travel increased in proportion to new jobs. Other travel purposes increased at even greater rates, causing a large overall increase in total trips. The greatest change of all occurred in vehicle- miles traveled, 3 Travel Behavior which best measures the demand for highway capacity. More and longer trips pushed up vehicle miles by 130 percent in 20 years. See Figure 1. Click HERE for graphic. Dispersal Twenty years of growth in jobs and homes has pushed the margins of development in the Twin Cities area further and further from the historical centers of St Paul and Minneapolis. This outward reach of urban development had two effects on regional travel. The first was that most new daily travel occurs in the developed and developing suburbs. Demand for travel destined to either Minneapolis or St Paul is just over one in four regional trips. The second effect of outward growth is the dispersing of trip origins and destinations, leading to more crosstown and circumferential travel patterns. Even though jobs are following homes to the suburbs, the average distances between places are increasing. This is mirrored most directly in the average distance of a daily trip, which has increased by 21 percent. In the past two decades: -The share of land in urban use within the region grew 35 percent. This increase occurred at the region's margins, primarily in the policy areas designated as developing suburbs. -In 1970, 54 percent of the region's households were located outside Minneapolis and St Paul; by 1 990, 69 percent were outside the two cities. The number of households in the central cities did, however, increase by 2.2 percent-all in the city of St Paul. See Map 1. -The total number of jobs in the region 4 Summary Report Click HERE for graphic. 5 Travel Behavior Click HERE for graphic. 6 increased from 853,000 to 1,289,000; nea all net growth occurred in the suburbs or beyond. Between 1970 and 1990, the percentage of regional jobs located outside the central cities increased from 44 to 63 percent See Map 2. -Each of the above influenced the spreading out of travel origins and destinations. Lifestyle As lifestyles change, travel behavior adapts follow. Getting a driver's license, or a job, forming a household, and meeting the needs household members-each of these influences travel. How important is mobility? Somewhere between 15 and 20 percent of the average household budget goes to transportation. A number of important urban lifestyle changes in the past 20 years have impacted travel, including: -A larger percentage of the total population is employed full or part time. In 1970, it was 40 percent By 1990, 54 percent of the population was employed, generating both more work trips and more personal income. -More women are in the work force. The participation rate of women in the work force jumped almost 19 percent from 1970 to 1990. By 1990, 68 percent of women aged 16 and over were in the work force. The participation rate for men stayed nearly constant at 82 percent. See Figure 2. -The percent of families that have two or more workers grew from 38 percent in 1970 to 69 percent in 1990. -More people in the region have driver's licenses. The total grew from 1,220,000 in 1970 to 1,814,000 in 1990. The number of women with licenses grew to the same level as licensed men drivers. This had occurred by 1985. Historically a lower proportion of women drove cars. Persons without licenses Click HERE for graphic. 7 Travel Behavior use transit because driving is not an option for them. As more can drive they tend to make driving their choice. See Figure 3. -People over age 65 are more mobile as retirement lifestyles change. In 1970, approximately 66 percent of those 65 and older had driver's licenses; in 1990, 84 percent of senior citizens had driver's licenses. -More families have two cars. In 1970, 33 percent of all households had two or more cars. In 1990, the figure jumped to 65 percent These changes are reflected in the growing use of the region's highways. They have not, however, resulted in more demand for public transit service. Approximately the same number of public transit trips were made in 1990 as in 1970. But automobiles dominate travel to an even greater degree today because so many people have shifted from car-pooling to driving alone during the last two decades. On a daily basis, drive-alone travel now accounts for almost half of all trip-making and 80 percent of home- to-work travel. This unprecedented growth in auto travel has provided unparalleled personal mobility. Unfortunately, it is also creating growing concern about energy use and the health of the environment. Further, it means that the nine percent of households without automobiles do not have equal access to travel. Households without autos make less than one-quarter the daily number of trip of households reporting that they have cars. Click HERE for graphic. 8 Summary Report 2 . REGIONAL TRAVEL The Average Travel Day The Travel Behavior Inventory (TBI) uses the home interview data to portray a typical weekday of auto, carpool and bus travel in the Twin Cities metropolitan area. The basic unit of the TBI is the 'person trip.' This is a journey in a vehicle as either a driver or passenger. In some cases, "vehicle trips" will be used in this report. This is a trip by a vehicle, regardless of the number of people in it. When vehicle trips are cited as the unit of measure, it will be noted. For the most part, tables in this report include only auto and public bus travel (they exclude pedestrian, bicycle and school-bus trips) because auto and public buses create the overwhelming majority of demand for highways in the region. The seven-county metropolitan area's transportation system accommodated an average of 9,305,600 person-trips on an average weekday in 1990. Of this travel, 8,860,600 of the trips were by residents of the seven counties Some travel by residents of the region (162,500 person-trips daily) consists of trips to and/or from places outside the seven counties. Most of the travel by residents (98 percent, or 8,698,100 daily person-trips) occurs entirely within the borders of the seven counties. This resident- generated travel produces 2,635,050 hours of personal travel time each day-about one hour per resident. These trips cover 55,350,650 miles, or an average of 24 miles per day per regional resident.1 On a typical weekday, about 83.5 percent of all regional residents make one or more trips, each traveler devoting an average of about 15.8 minutes to a trip. During the course of the day, residents make an average of 3.87 trips. Over 93 percent of all trips are by automobile drivers and passengers. On an average day, regional residents generate: -6,417,500 trips as automobile drivers (72.4%); -1,857,100 trips as automobile passengers (21.0%); -225,100 trips as public transit passengers (2.5%); -311,800 trips as school bus passengers (3.5%); and -49,1 00 trips by other vehicles-motorcycles, taxis, etc. (0.6%) The regional transportation system accommodates 6,711,300 vehicle trips in automobiles on an average weekday and another 320,000 estimated trips in heavy commercial vehicles including buses. Total auto trips include those by both residents and nonresidents. ----------------------------------- 1This compares to the 1.5 hours spent and 32 miles traveled per day cited in other parts of this report. The one-hour, 24-mile average is for all regional residents; the 1.5 hour, 32-mile average is for all residents who make at least one trip In a given day. 9 Travel Behavior The Twin Cities metropolitan area contains 2,968 square miles of land and water area. In this area in 1990 there were: -2,288,721 persons; -875,504 households; -2,103,600 persons five years or older, -1,243,637 employed full-or part-time; and -602,600 full-or part-time students. The 875,504 households occupy a portion 922,224 housing units (there is a vacancy rate at any one time of about five percent). Occupied housing units by type: -604,893 are single-family including mobile homes (69.1%); -38,438 are two-family (4.4%); 232,173 are multifamily (26.5%); and -593,959 are owner pied (67.9%); and 281,545 are renter- occupied (32.1%). The average household: -has 2.56 members; -owns 1.74 autos; and -produces 10.1 person-trips per day. Travel has a daily rhythm and a majority of metropolitan citizens travel at one time or another during the day. The hourly movement of people to and from work, shopping, school and other destinations is a pattern that has remained relatively unchanged for decades. The home is critical to the daily cycle because most metropolitan traffic (95.2 percent) is the result of travel by the region's own residents, and most travel (about 67 percent) has one end of the trip at the home of the trip-maker. In the course of an average weekday, the volume of travel fluctuates from only a few thousand person-trips in the early morning hours, to over 800,000 per hour during the afternoon peak travel hours. Figure 4 indicates the volume of trips by time of day. Click HERE for graphic. Travel purpose varies over the day from mostly work trips in the morning hours, to mostly trips to home in the evening and night- 10 Summary Report Click HERE for graphic. time hours (see Figure 5). Two other interesting findings emerge from the figures. First, shopping constitutes a significant proportion of trips throughout the 24-hour period. The majority of shopping trips occur between 9 a.m. to 9 p.m.; however, compared to 1970, shopping now occurs more often in the afternoon and evening hours. Click HERE for graphic. The second finding emerges from the comparison of trends indicated by the work-bound and home-bound trips. 11 Travel Behavior Whereas the work-bound trips primarily start in the morning hours and begin to taper off by 8 a.m., the home-bound trips exhibit a significantly different pattern. The proportion of home- bound trips begins increasing in the same time period as the work- bound trips begin to decrease. But home-bound trips continue to increase until approximately 5 p.m., when other trips become more predominant for a two-hour period. The home-bound trips then again constitute the major portion of the trip starts until 3 a.m. However, looking only at Figure 5, which presents the daily proportions of trip purposes, can be misleading. Figure 6 presents the same trip data, but charts the absolute number of trip starts for each purpose. This figure shows the home-bound trip starts generally decreasing after reaching a peak at 5 p.m., whereas the previous figure indicates an apparent increase in home-bound trip starts. Obviously, the apparent surge in home-bound activity shown in Figure 5 in the evening hours is more a result of the general decrease of other trip purposes than to a significant increase in home-bound trips. Through and External Travel On an average weekday, 6,711,300 automobiles make trips in the seven-county metropolitan area. Of these trips, 293,800 automobiles are entering, leaving, or passing through the region. Through-travel (autos passing through the area) and external travel (traffic that has one end of the trip outside the region) have a minimal impact on regional highway travel or highway capacity need. Together, they comprise about 4.4 percent of the total travel. Alone, external traffic represents about 4.0 percent. Click HERE for graphic. 12 Summary Report Click HERE for graphic. The total number of vehicles involved in through-traffic on an average day is 328,500: 89 percent are automobiles and 11 percent are trucks. Travel through the region is somewhat time-dependent. Figure 7 illustrates that although through-trips occur all during the day, they reach their highest levels and peak during midday. Through and external travel generally is not concentrated in location, as shown in Map 3. However, the influence of the interstate highways can be observed in the counts at the region's borders. About 74,000 workers arrive daily to work in the region from places outside the seven counties. Approximately 24,000 residents depart from the region daily to work in places outside the seven counties. Daily person trips leaving the region: 218,400. Daily person trips entering the region: 216,400. Daily person trips passing through the region: 51,400. 13 Travel Behavior Where People Travel-Origins and Destinations The traditional view of trip origins and destinations is "into the city in the morning and back to the suburbs in the evening." In the Twin Cities area, trip orientation has always been influenced by the fact that there were two downtowns to go to, and that both Minne-apolis and St. Paul were surrounded by bedroom suburbs in the immediate post- WWII period. As a result, the region has never had one central major traffic generator similar to the Chicago Loop. This "morning in and evening out" image is out of date due to two major developments. First, destinations such as workplaces and shopping locations have built up in the suburbs Click HERE for graphic. 14 Summary Report along with the bedrooms. Secondly, the region's interstate and other freeways form a network crossing and surrounding the central cities and suburbs. This network facilitates trips among and between the suburbs and cities in more than just a radial fashion. Because of a low density, dispersed pattern of development surrounding the two older central cities, a dispersed pattern of travel has developed. If a picture were taken of all the trip tracks it would look like a ball of string. Grouping travel origins and destinations by major geographic areas (the two central cities and the counties outside the cities) shows that no one area, suburban or central city, is the focus of travel in the region. Figure 8 summarizes patterns of trip origins and destinations for movements within and between the two central cities and the counties. The numbers shown are percentages of all daily trip movements. Lines between the circles show movements from county to county or city, and figures within circles indicate the percent of daily trips that both originate and end in that area. The south Hennepin County suburbs generate and retain just over 14 percent of all regional travel, and attract another eight to nine percent of all travel. The two central cities generate and retain about 18 percent of regional travel and attract another six to seven percent. Three out of every four trips in the region are suburban or rural. One in four trips involves the central cities. How People Travel - Modes In the Twin Cities there are numerous modes of travel: walking, biking, using a car, (including pickups, vans and motorcycles) and riding in a bus or school bus. Car users may drive alone or ride with another person. Depending on where people live and where they are going, they may have no choice but to use a car. Where public transit can be used the selection is related to cost, convenience, personal preference, habit and other considerations. Walking and biking are available to some in good weather and with short enough distances, but for the most part are not covered in this study. Figure 9 and Tables 1 and 2 summarize TBI findings regarding vehicle mode of travel. Click HERE for graphic. Travel by car accounts for some 93.4 percent of all person-trips made by residents of the region. The selection of travel mode varies 15 Travel Behavior Click HERE for graphic. according to the purpose of the travel. Fewer auto passenger trips are made to work, a higher portion of these trips are made by auto drivers. Public transit use is at its highest during peak-hour periods because transit is so closely related to work travel. Travelers also use a combination of transit and another mode during the same day. Ten percent of households, containing five percent of the region's population, reported using transit on the average travel day. Transit also carries seven out of every 100 trips starting in the central cities. Table 1 compares the characteristic profiles of auto drivers, auto passengers and public transit passengers. Especially significant is the role of transit in relation to the Central Business Districts (CBDs). The public-transit share of all trips to or from the CBD areas is 24.9 percent. Also, whereas public-transit comprises only 16 Summary Report Click HERE for graphic. 2.5 percent of all trips, it comprises just over 5.2 percent of trips to or from work, 7.4 percent of all trips by central city residents, and 3.6 percent of trips by the elderly. Demographics and Travel Both age and gender differences can be seen when looking at personal rates of travel. Between 1970 and 1990 there have been noticeable changes in travel rates for both women and men. In 1970 young men made the most trips per day. In 1970 older persons made significantly fewer trips, per capita, than younger travelers. By 1990, trip-making by older persons in the region and by women had changed significantly. Figures 10 and 11 show average daily trips for men and women by age. By 1990 the highest rates of travel were for men in the 40- to 49- year-old age group. Overall the rate of travel across all age groups was no different for men than women (4.35 trips per traveler compared to 4.34). Trip rates for persons 70 years of age or more have doubled for both men and women. Across all ages the frequency of daily travel is up. Figures 10 and 11 dearly show the greatest 17 Travel Behavior Click HERE for graphic. 18 Summary Report Click HERE for graphic. increases have been among older travelers and women. Use of the automobile varies greatly depending on both sex and age. The two youngest age groups are primarily passengers. Beyond age 19, men are almost always auto drivers. Women were found to be passengers more frequently. Figures 12 and 13 show the mode by age and gender. Other factors also influence the travel choice, such as the economic circumstances of the household, ability to drive a car, availability of a vehicle, travel time, and simple access to modes of transportation. Map 4 shows average auto ownership in the region aggregated to TBI subregions. The area of greatest transit use is in the central cities where autos per household are the fewest. Such households 19 Travel Behavior Click HERE for graphic. 20 Summary Report make far more transit trips. (See Figures 14 and 15.) Figure 14 shows the impact of the two-or-more-car households on daily travel. Such households account for over three-fourths of all travel. The 41 percent of households with one or no cars make less than 25 percent of all daily person trips. Conversely, as shown in Figure 15, these households make 71 percent of all transit trips. Click HERE for graphic. All travelers consider time in choosing how make trips. Use of the car normally means a shorter trip time, unless parking and walking at one end of the trip become a factor. Transit 21 Travel Behavior trips made in 1990 had trip times, on the average, of 1 0 to 1 5 minutes longer than by car. Table 3 gives regional trip times by purpose and mode. The average time to work is 21.2 minutes. The fastest mode for home-based work trips is auto passenger. The average time of 19.2 minutes (as opposed to 20.7 minutes for drivers) probably reflects the passenger's shorter trip as they are picked up or dropped off on the way by the driver. The difference between auto driver and passenger times was more pronounced in 1970: 19.2 minutes for the driver and 16.9 minutes for the passenger. The increasing presence of car pools within the same household may be the cause for converging travel times. Traveling to work by public transit averages 31.3 minutes, about 50 percent longer than by car. This ratio improved since 1970 when transit work trips averaged 33.6 minutes, 70 percent longer than by car. Table 4 gives the average trip distances of the major purposes and modes. While 1990 trip times remain similar to 1970, trip distances increased. The average distance traveled to work is 9.2 miles. Travelers that use public transit average shorter trips to work. Click HERE for graphic. 22 Summary Report The Role of Transit The region's transportation system is very oriented to privately-owned vehicles using an extensive network of roadways and highways. As outward growth from the central cities continues, suburban residents often find themselves with no other choice than the automobile to make their trips. The TBI Home Interview Survey found that only 2.5 percent o the total trips made were on public transit. Over 70 percent more trips were carried by school buses than were carried by public transit Nonetheless, public transit is an important part of the regions's transportation system. A significant proportion of the developed portion of the metropolitan area is served by public bus and Metro Mobility (a service for people with disabilities) transit. Residents of the region in 1990 made an average of 225,100 transit trips each weekday. Ten percent of all households reported at least one trip by bus each weekday. Map 5 illustrates the area of the region that is served by midday public transit service. Click HERE for graphic. 23 Travel Behavior To check the home interview and supplement its small sample of transit users, independent surveys were made in 1988 and updated in 1990. The surveys were conducted on board regular-route buses. The on-board surveys validated the total number of trips reported in the home interview. These surveys, and the home interview, found that walking was the primary means of reaching the bus. Seventy eight percent of the bus users walked to the bus and just over eighty percent then walked to their final destination after getting off the bus. Walking to the bus means that the person walked from wherever their trip actually started to the bus stop. The primary use of the bus system was for trips between home and work. Over 59 percent of the trips were for this purpose. The remainder of the trips were generally evenly distributed among trips for shopping, school, university/college, personal business and other. Three-quarters of bus riders ride only one bus in their trip, and almost twenty-four percent ride two (use a transfer).. Bus riders are predominantly between the ages of 18 and 44, and almost two-thirds are women. Twenty-six percent of the riders are "captive," in that their household had no vehicles available, and twenty-seven percent of riders stated that their household vehicle was not available for them to make their trip. Forty-six percent of the riders stated that a vehicle, other than the bus, was available for them to use to make the trip. Thus, on the average, bus riders were roughly split 50-50 between choice and captive. The average transit trip length (in minutes) is the shortest it has been in years. In 1990, the average trip length was 26 minutes, compared to 28 minutes in 1958 and 33 minutes in 1970. This decrease in average trip time is due in part to the increased use of cars for longer trips. Increase in the speed of public transit has been limited to higher speed express service on the freeways, most of which was not available in 1970. Regular-route speeds have not increased appreciably. Nonetheless, on the average, bus trips are made in good time and overall average distances traveled by bus have increased, so one can conclude that transit service in 1990 appears to be superior to 1970. Figure 16 shows the distribution of bus trips by annual household income of the trip maker. The reported average income of bus riders from the on-board survey was below regional Click HERE for graphic. 24 Summary Report average income, and 40 percent of transit trips come from households without cars. This shows that bus riders are more often members of lower income households in comparison to other travelers in the region. Figure 17 summarizes patterns of transit trip origins and destinations for movements within and between the two central cities and the counties. The numbers shown are percentages of all daily transit trip movements. Lines between the circles show movements from county to county or city, and figures within circles indicate the percent of daily transit trips that both originate and end in that area. Sixty-five percent of all transit travel never leaves the central cities. Only six percent of transit trips occur in the areas entirely outside the Click HERE for graphic. 25 Travel Behavior central cities. Of the remaining approximately 30 percent, all trips have one end in one of the central cities. As measured by average daily trip-making, transit within the suburbs is almost nonexistent. While the concentration of transit travel in the central cities corresponds to lower income levels and greater development densities, it also reflects the availability of transit service. The Role of the Auto Auto ownership has exploded over the last 20 years. Seven- county residents owned approximately 1,520,600 vehicles in 1990, about 1.7 per household. There are about 1.5 persons per automobile in the region. In contrast the 1970 TBI reported that there were 1.25 automobiles per household and 2.61 persons per automobile. It is dear that people have become increasingly reliant on cars for their travel. One important influence on this trend has been the increase in the number of people who are employed. With paid work people have the means to buy cars. Table 5 evaluates the relative characteristics of households and the relationship to the number of automobiles owned. Households owning no cars tend to be either one- or two-person households, lower income and more often located in the center cities (see Map 6, Percent of Households With No Cars). As would be these households generate the larger share of all transit travel. Map 7 shows the distribution of autos per household by TBI subregion. With the exception of southern Dakota County, there is a Click HERE for graphic. 26 Summary Report Click HERE for graphic. 27 Travel Behavior Click HERE for graphic. 28 Summary Report direct correlation between more cars per household and distance outward from the center of the region. The first-ring suburbs and central cities average fewer than two cars per household, while the outer suburbs and rural' areas have averages near or greater than two. Auto ownership continues to grow in the region (see Table 6). Not only has the share of households without a car declined, but the share with two or more cars has greatly increased. As data back to 1958 shows, this is a very longterm trend. But it seems to be slowing; the rate of change in all categories was much smaller in the last 10 years. Income and auto ownership are directly related; as income rises the number of automobiles available to a household increases (see Figure 18). Click HERE for graphic. Click HERE for graphic. Income does more than influence the number of cars a household owns. It also affects the number of trips made and distance traveled per household. Households with two or more cars represent only 58 percent of households, but 29 Travel Behavior make over 75 percent of regional trips. As income goes up, both the number of trips (see Figure 19) and the length of those trips increase. Although the length of the trips increases, the duration of those trips in minutes remains generally within a narrow time band of 17 to 19 minutes, as is illustrated in Figure 20. Trip length increases by about 40 percent for higher-income households (Figure 21). Click HERE for graphic. 30 Summary Report Auto Occupancy An average passenger vehicle traveling in the Twin Cities region had 1.29 occupants in 1990, compared to 1.50 in 1970. The average occupancy of an auto varies according to the driver's purpose for the trip, as is shown in Table 7. The table also illustrates how occupancy has declined more sharply in the last 20 years compared to long-term data back to 1950. This factor may already have played itself out in terms of real effect on the need for highway capacity. The work-trip occupancy, which effects peak- lane demand, can scarcely fall much further. The region's residents spend approximately 2,635,000 total daily person-hours traveling about 55,350,600 miles. Of the 2 million residents who are five years of age or older, about 336,500-or 16.5 percent-do not make a trip on a typical weekday. The average metro traveler spends 92 minutes in travel per day-almost double the 1970 average of just under 50 minutes-making 5.2 trips. (Note that the trip rate for, those who actually make trips is higher than that reported per capita earlier in the report; the per-capita calculation includes nontravelers.) In 92 Click HERE for graphic. Click HERE for graphic. 31 Travel Behavior minutes the average traveler covers 32 miles (up from 19.6 in 1970), at an average overall rate of 21 miles per hour. The average distance for all trips is 5.9 miles, and the average time is 15.8 minutes (see Table 8). Auto driver trips are longer in miles than transit trips, but considerably shorter in time. Maps 8 and 9 illustrate average trip distance and times in the seven-county area by TBI subregions. Trips to the two CBDs exhibit some special characteristics. These two special generators would be to attract trips from all over the region. When comparing data for the two CBDs to regional averages it appears that the Minneapolis CBD attracts trips that are longer in time and greater in distance. St. Paul, on the other hand, shows shorter transit travel. Click HERE for graphic. In the 32-year span from 1958 to 1990, a time of increasing population and urbanization, 32 Summary Report Click HERE for graphic. 33 Travel Behavior Click HERE for graphic. 34 Summary Report the average time of driver trips has shortened. The share of trips that take 12 minutes or less has grown significantly (see Figure 22). Click HERE for graphic. Click HERE for graphic. Forty years ago, when there were no freeways and a higher proportion of trips were made on transit, only one-third of travelers made trips of less than 12 minutes. With the introduction of freeways and the shift to the auto (which was well along by 1970) over 55 percent of trips were 12 minutes or less. Since 1970 the trend has reversed: in 1990 only 48 percent of travel occurs as these very short trips. With the continued expansion of urban development at the margins of the region, and assuming that very few new freeways will be built in the next 20 years, average trip times should continue to increase. 35 Travel Behavior Peak-Period Travel Peak-period travel has historically been a twice-daily phenomenon. During the peak periods, travel makes the most demands on the capacity of the regional transportation system. Generally, continuation of this trend is confirmed by the 1990 Travel Behavior Inventory. However, the percentage of total daily travel of the two "peak' periods has declined. Figure 23 illustrates the daily pattern of trip starts for 1949, 1970 and 1990. It can be observed that in 1949, daily traffic reached higher peaks (as a percentage of total daily traffic) than it did in later surveys. This is not to say that the volumes in the peak periods decreased, only that their share of the average daily weekday traffic decreased, and that more of that daily traffic is being carried in the off-peak hours. In Figure 24, the average number of persons traveling per quarter-hour is illustrated. The upper line shows the volume of trips already in motion and the lower line shows trip starts. The two lines exhibit the same shape because, on the average, a trip is one-quarter of an hour long, so the volume of trips in motion follows a curve similar to the time persons start their trips. Because of the effect of trip duration, there are normally two to two-and-a-half more trips in motion to every new trip starting. This figure also reveals just how many persons are actually taking a trip at any one moment. The values shown are accumulated for quarter-hour intervals. The curves reveal that from 6 a.m. to 9 p.m. there are always I 1 0,000 or more persons traveling. As seen earlier, there are two distinct peaks of trip volumes, one of nearly 200,000 person trips per quarter-hour in the morning and one of over 250,000 in the afternoon. During this 15-hour period, 5 to 11 percent of the population over age five is always on the move in a vehicle somewhere in the region. Click HERE for graphic. The midday volume of trips continues at roughly two-thirds of the morning level, and there is a two-hour period in the afternoon that equals or exceeds the morning one-hour peak. The experience of congestion is much Summary Report Click HERE for graphic. greater in the afternoon as the highway system builds to and maintains the highest traffic levels of the day. Click HERE for graphic. 37 Travel Behavior characteristics of person trips in the region. It is a common belief that rush-hour traffic is largely made up of work-oriented travelers. This trip purpose contributes a large number of peak trips to the region's road system, however, not the majority. Only in the morning peak hour does work-oriented traffic provide 50 percent or more of the trips (see Figure 25). The afternoon peak period is dominated by nonwork travel. Figure 26 presents the same information in absolute numbers. Click HERE for graphic. Figure 27 illustrates the peaking characteristics of selected heavy traffic generators in the metropolitan region. 38 Summary Report Click HERE for graphic.2 39 Travel Behavior There is considerable variation in the peaking characteristics, depending on the particular site. Shopping centers tend to have more even traffic patterns compared to sites like the airport or the university, which have morning peaks of travel. See also Figures 31 and 32 in Chapter 3, which show peaking characteristics of the two central business districts. Highway Speeds The Highway Speeds Study obtained a sample of the operating speeds on metropolitan area roadways. Speed data was collected to determine how speeds vary by time of day and by the direction of travel (inbound or out bound). Information on speeds was collected on a variety of road types, such as freeways) multi-lane divided highways, multi-lane undivided highways and high-volume, two-lane roads. The survey gathered data from over 296 miles of roadway. Table 10 summarizes the findings of the highway speed study. Click HERE for graphic. The average overall speeds observed reveal a regional freeway system that gives very good service. During the evening peaks when the most traffic is on the system, the average for all segments surveyed was about 45 miles per hour. Morning speeds were about 50 miles per hour. Midday speeds, on the average, are 5 to 10 miles per hour higher than the slowest speeds of the day. See Figure 28. Click HERE for graphic. 40 Summary Report 3. TRAVEL and LAND USE The nature of a location strongly influences traffic by the travel it attracts or generates. For example, a single farmstead generates little traffic, a regional shopping center generates a lot. Data from the home interview survey travel diaries is used to determine residential travel generation. Using factors such as the number of household members and cars available, the generation rates at the home end of a trip can be determined with some precision. Residential trip rates have proven to be more predictable than nonresidential rates, ranging from six to eight daily vehicle. trips per household. Nonresidential areas, such as offices and shopping centers, show greater variability in traffic generation than do homes. A busy convenience store with a gas station can generate hundreds of trips in a day, while a dental office next door with the same number employees on a similar-sized lot will generate only a few dozen. The purpose of this chapter is to illustrate the dynamic effect on traffic of change in location and intensity of land use. This chapter looks at land use by major regional divisions and special locations. Location by the Metropolitan Council's development framework policy areas is considered first.1 The policy areas are the Central Cities, Fully Developed Suburbs, Developing Suburbs and Rural Areas. In the suburbs and rural areas, the car is king; the central cities see more use of public transit Other special land-use locations were surveyed as "special generators". These were the Minneapolis and St Paul Central Business Districts, the University of Minnesota East Bank Campus and the Minneapolis-St. Paul International Airport Each area is unique in the nature of the travel it attracts. This, in turn, leads to a special travel character, including more-than-usual ridesharing- in both car pools and public transit Central City, Suburbs and Rural Areas A trip outward from the center of either Minneapolis or St Paul is a journey through time and style in development The older parts of the cities lie at their centers, although the exact centers have been rebuilt several times and are not as historic as the blocks surrounding them. The center and older neighborhoods have and continue to be more densely covered with buildings. Population concentrates in the middle of the region but, journeying into the suburbs, becomes more dispersed as the rural fringes of the metro area are reached. Building practices vary depending on age of area ---------------------------------- 1 The areas used in this report are generalized representations of the development framework areas. For a detailed description of the areas see the Council's Metropolitan Development and Investment Framework, published in 1988. 41 Travel Behavior and neighborhood. In older areas, for instance, the garage is at the back of the property served by an alley. In houses built later, the garage was in the back but the drive was alongside the house. Finally, garages were attached to the house, resulting in wider lots and fewer homes per square mile. Neighborhood and comer stores along commercial streets change to groupings of retail and business buildings separated from homes or concentrated in shopping centers of varying sizes. A close spaced grid of streets and alleys with frequently provided bus routes gives way to fewer, more curvilinear roads and highways, mainly devoid of transit service. Patterns of development, and street and highway networks, are reflected in travel patterns and habits, creating differing needs and opportunities for the driver or transit user. Tables II to 1 5 summarize some of the key relationships between city, suburb and rural area. Table 11 reveals some significant differences between the central cities, the suburbs and rural areas that are reflected in daily travel. The most households are in the developing suburbs; the most jobs are in the central cities. Jobs are more available in the fully developed suburbs where nearly two jobs can be found for each household. Both car ownership and family size increase from the central cities outward. The developed suburbs show households slightly larger than the central cities, and have more cars per household. In the developing suburbs and rural areas the typical household has three persons and two cars. A surplus of jobs, smaller households and fewer cars are found in the central cities. Lower car ownership is partly to be expected because fewer persons per household means less need for cars. The disparity is amplified by those not owning cars at all. Seventy percent of all households without cars are in the central cities. They form a captive group of transit users whose mobility is dependent on bus or car-pool arrangements. The fewest jobs are in the rural areas. There are 1.3 to 1.5 jobs for each employed worker living in Minneapolis and St Paul. But the surplus of available jobs does not mean that central-city residents work there. In fact, only 43 percent of Minneapolis job holders and 39 percent of St. Paul job holders actually work in their home city. This fact underscores the degree to which commuting has changed. Commuters no longer travel inward in the morning and outward at night. Instead they commute throughout the region, with suburb-to-suburb commuting outweighing suburb to city. Click HERE for graphic. The pattern of commuting travel is illustrated in Figure 29 for movements between and within the central cities and the counties outside of the central cities. These 10 geographic subareas 42 Summary Report Click HERE for graphic. 43 Travel Behavior exhibit diverse patterns of movement that depend heavily on the flexibility of the highway network and drive-alone mode. The south half of Hennepin County generates and retains just under 11 percent of all home-to-work travel. When commuting from other areas is included, south Hennepin County suburbs receive nearly one in five (19.6 percent) of all regional home-based work trips. Minneapolis and St Paul combined are the destinations of slightly less than one in three (30 percent) of all work trips, including trips from within and between the two cities. This means that seven of every ten work trips are destined to suburban or rural destinations outside of the two central cities. Click HERE for graphic. Table 12 indicates that the developing suburbs experience nearly a million more trips per day than either the central cities or fully developed suburbs. In part this is to be expected because the developing suburbs have the most households and nearly as many jobs as the central cities. However, it also reflects the large household size and greater car ownership found in the newer suburbs. Nearly 80 percent of all transit travel occurs within the central cities. The proportion of travel by persons driving alone is nearly the same in all areas, about half of all trips, ranging from 48 percent in the developing suburbs to 52 percent in the fully developed suburbs. Click HERE for graphic. 44 Summary Report When trip purposes are tabulated by the development framework area of destination (Table 13), a remarkable uniformity appears, with one or two exceptions. Across all trip purposes the number of trips is about what would be expected given the relative number of households in each area. There are two exceptions to the generalization, which reflect the impact of lifestyle on travel. The developing suburbs have twice as many school trips as the central cities-from only 20 percent more households. Compared to the older suburbs, there are nearly three times the school trips from only 55 percent more households. This reflects the concentration of younger households with school-age children in the outer suburbs. Click HERE for graphic. Click HERE for graphic. The effect of density on travel is revealed by average trip distance for each of the, development areas. (See Tables 14 and 15.) As expected, trips are shorter for drivers living in the central cities and fully developed suburbs, and longer for rural and developing suburban drivers. This relationship holds true for all trip purposes except the category "non-home-based other," where developed suburban trips are slightly less than central city trips. The relationship between shorter trips in inner 45 Travel Behavior locations and longer trips in outer locations also holds true for transit trips across all trip-purpose categories. Tables 14 and 15 indicate those living in the center of the region are meeting their travel needs running up fewer car miles. (See also Map 8, in Chapter Two, indicating total. trip distances.) Rural commuters travel 50 percent further than central-city commuters. Suburban bus commuters go up to two times as far. The difference between central city and rural driving time is not large. Drivers appear to travel the same reported number of minutes, give or take 15 percent (The actual difference is only two minutes or less for each trip purpose.) The Central Business Districts In the 20 years between 1970 and 1990, the Central Business Districts (CBDS) saw significant changes in the organization of their space. Many older buildings are gone, and new office and retail complexes have been built on the cleared sites. In spite of all the demolition and construction, data from the U.S. Census and state Department of Jobs and Training reveal that the rebuilding of the CBDs has been accompanied by only modest changes in overall numbers of downtown residents and employees. Numbers of workers far exceed residents in the two CBDS. Table 16 summarizes the changes over the 20-year period. Table 16 Summary of Central Business District Change in Population and Employment--1970 to 1990 ST. PAUL CBD DATA 1970 1980 1990 CHANGE 70-90 Population 2,835 2,474 4,068 +1,233 Households 1,768 1,770 2,681 +913 Employment 54,200 51,000 56,880 +2,580 MINNEAPOLIS CBD DATA 1970 1980 1990 CHANGE 70-90 Population 17,425 14,262 16,194 -1,231 Households 10,813 9,394 9,860 -953 Employment 107,843 113,591 123,032 +15,190 Functional changes have taken place in the CBDs of most large urban areas, including those of Minneapolis and St. Paul. The two downtowns have been shifting from their past role as retail and industrial centers to more office-oriented uses. As might be expected given this modest growth, the CBDs have stabilized as travel generators. In fact, looking back as far as 1949 when such data was first collected, there has been a drop in person-trips arriving in the CBDs (see Table 17). One way of measuring the role of the CBD as trip attractor is to express the number of trips 46 Summary Report Click HERE for graphic. Click HERE for graphic. 47 Travel Behavior to them per resident This statistic is shown over time in Figure 30. In the post-WWII period the CBDs attracted the equivalent of one trip a day from 33 percent of the region's population. Recently that has become the equivalent of one trip a day from about 12 percent of the population. Both St. Paul and Minneapolis have experienced long-term declines in the number of person trips arriving in their respective CBDS. Table 18 shows the changing role of the CBDS. A major decline in the number of shopping trips to the CBDs is largely responsible for the overall decline of trips to these areas. Table 19 shows the share of daily trips in the region that orient to the CBDS. Both city centers concentrate work travel and transit travel but play a small role in attracting total travel. The degree to which shopping trips no longer concentrate in the CBDs is apparent as well. Figures 31 and 32 show the pattern of arrivals in the morning peak period for the CBDS. The concentration of high volumes of trips in the core areas of each center requires peak deployment of transit buses in the day. Less than half as many buses are required in the off peak as are running from 6 to 9 a.m. In the evening the bus fleet expands again for outward movements. Maps 10 and 11 depict the geographic travel-sheds to the two CBDS. Each downtown has its own distinct travel-shed. Trips destined for the Minneapolis CBD originate in a relatively uniform circumferential pattern with the CBD at the center. Trip origins to the Minneapolis CBD are greatest from within the city, which generates 47 percent of all CBD trips. The suburbs southwest of the CB contribute another 10 percent. The Minneapolis travel-shed also overlaps into the west half of St. Paul. Areas south of the Minnesota River in Scott and Dakota Counties do not contribute a significant portion of downtown Minneapolis travel. The travel-shed to St. Paul's downtown is to the east, to areas immediately north and south, plus the city itself Fifty percent of downtown St. Paul trips come from within St. Paul. The St. Paul travel-shed also overlaps into the south half of Minneapolis. This pattern of dispersed origins around the two most concentrated transit destinations causes the bus system to be routed and scheduled as two relatively separate operations. Table 19 Comparative Profile Central Business Districts Of All Trips Occurring on an Average Weekday Those Oriented To or From: Minneapolis CBD Saint Paul CBD Comprise 3.5% 2.3% Of All Person Trips Generate 3.0% 2.0% Of All Auto Driver Trips Generate 39.1% 17.2% Of All Transit Trips Spend 4.8% 2.7% Of All Time Spent in Travel Generate 7.7% 4.8% Of All Work Oriented Trips Generate 1.4% 0.6% Of All Shopping Trips 48 Summary Report Click HERE for graphic. 49 Travel Behavior Click HERE for graphic. 50 Summary Report Click HERE for graphic. 51 Travel Behavior Click HERE for graphic. 52 Summary Report University of Minnesota As part of the 1990 TBI, the main campus of the University of Minnesota was studied to determine the number of trips it generates. Traffic volume, occupancy, transit and pedestrian/bicycle trip counts were collected for an average weekday during the regular school year. In general terms, the study found that the Main Campus - East Bank generated 78,640 daily vehicular trips, with approximately nine percent of the total daily traffic in each of the peak hours. The study counted 35,590 pedestrians and 6,850 bicycles. The total number of person-trips was 122,260, with 51 percent in vehicles, 15 percent in public transit, 29 percent as pedestrians and 5 percent on bicycles. The East Bank campus attracts the second-largest volume of trips in the region, behind only downtown Minneapolis. Other information gathered concurrently indicates the campus area has a total daytime population of 38,680 comprised of residents, nonresidents and faculty/staff. Figure 33 illustrates the vehicle trips for the university over the 10-hour survey period. Click HERE for graphic. When pedestrian trips are added to those made by vehicles, the East Bank campus has three distinct peaks-morning, noon and afternoon. The vehicular traffic for the university shows only morning and afternoon peaks. Both are similar in size, unlike the regional pattern, which has significantly more trips in the afternoon peak. 53 Travel Behavior Figure 34 illustrates the volumes and peaking characteristics of the university person-trips by mode. Auto traffic is the predominant m choice only for the peak hours. During the d total person trips are more greatly affected by pedestrian and transit movements. This is not really surprising, considering the nature of a university campus and the movement of students from one class to the next. Click HERE for graphic. Minneapolis-St. Paul International Airport The Minneapolis-St Paul International Airport was surveyed as part of the 1990 TBI to determine the number of vehicle trips it generates. Included were interviews with a sample of travelers using rental cars, courtesy buses, taxis and limousines to leave the airport Travelers in the sample were primarily nonresidents visiting the area. The study area selected included the entire site. In addition, traffic volume counts were taken at several locations, shown in Table 20. Click HERE for graphic. Summary Report On the day of the survey, the morning peak-hour contained seven percent of the daily traffic, and the afternoon eight percent. The daily pattern of trips to and from the airport is shown in Figure 35. Although airport traffic does have a morning and afternoon peak these peaks are only about one-third higher than much of the rest of the day. Over 47 percent of the surveyed arriving travelers were bound for a hotel or motel from the airport, over 35 percent were bound for a workplace and almost 13 percent were bound for a residence. Over 79 percent were here on business. The destination of travelers departing the airport by taxis, rental cars, limousines and courtesy buses is shown in Table 21. Minneapolis attracts almost four times the number of travelers as does St. Paul, and Bloomington exceeds St. Paul by almost 50 percent. Arriving travelers generated about 8,200 vehicle trips, of which about 80 percent were rental cars. Click HERE for graphic. 55 Travel Behavior Click HERE for graphic. Click HERE for graphic. 56 Summary Report 4. MAJOR FINDINGS The findings of the 1990 Travel Behavior Inventory have provided a dear picture of how regional travel has changed since the last major survey was taken in 1970. But what does it mean for the future? Transportation infrastructure in the region and the nation faces a continuing crisis as long as demand for highways and transit seem to outrun our ability to pay for them. just how persistent will the long-term upward curve of demand be, and is there anything that government can do to curb it? This chapter looks at three factors critical to unraveling the long-term picture, how these factors have changed and what their future might be. These factors are: - Trip rates in relation to changing households; - Driving mode for work travel and all travel; and - Trip distances (both time and miles). Trip rates drive the entire demand for travel, but trip rates per household are only part of the picture. Both the mode people choose to get around and how far they travel can and have magnified the needs for highways and bus miles. The total amount of travel as measured by vehicle-miles traveled and bus miles of service grew much more than was to be expected from the simple increase in the number of trips made. This chapter concludes with a look at the future of mobility in the region, in light of the travel-demand trends projected from the interplay of demographics, trip mode and trip distance. Trip Rates Certainly the most dramatic factor in the long-term increase in travel demand over the past 50 years is the increase in the average daily rate of trips per person. This statistic has been accepted by most analysts, both lay and expert, as evidence of the increasing mobility of contemporary society. Figure 36 shows how this rate has more than doubled since first measured in the Twin Cities in the early post-WWII period. It is important to also evaluate rate per household, because households form the basic economic and social unit in our society. In spite of the large number of single-person households (25 percent of all households), 90 percent of all persons still live in two or more person households. These households make more trips per capita than single-person households. Table 22 compares household trip rates for the past 20 years to per-capita rates and two other critical factors-household size and workers per household. It is significant that 57 Travel Behavior Click HERE for graphic. Click HERE for graphic. 58 Summary Report household trip rates increased 26 percent from 1970 to 1990, while per capita trip rates increased 44 percent. The shrinking number o persons per household was accompanied by a significant increase in the average age of the population over that period. People entered the years of their lives when they travel more. This age change was also reflected in the increase in the number of workers per household. As long as there are more workers per household, more work trips are likely to be made. When trip rates per household are broken down by purpose and household size, a 20-year persistent trend to increased trip-making can be seen. Table 23 shows by shaded cells those household classes (primarily in the larger households) where 1982 rates were higher than 1990. This is a counter trend to the overall upward change. The decline in home-based-other trips for larger households was partly a shift to higher rates of travel for non home-based trips. Overall, it is not possible to conclude that the basic trip rates are departing from the long-term upward movement The increased frequency with which people make trips equals the impact of household and job growth in the explosion of regional travel in the last 20 years. Click HERE for graphic. 59 Summary Report Click HERE for graphic. 61 Travel Behavior Driving Alone Driving alone is the way most people in the region travel, especially for trips to work. Because this habit has developed slowly, its importance was not clearly recognized even as the trend continued. Many changes accompanied this trend. These have included the expanding role of women in the paid labor force, and the reduction in family size as working couples have fewer children and spend more hours out at jobs. Seniors who were raised as drivers travel more than did their parents. All these factors lead to more personal activity in any day, and more activity leads to increased travel. Driving alone fees the traveler from the schedules of others. The trend to single occupancy in one's own car has taken hold in response to the desire for personal freedom of movement. If traffic had grown only in proportion to new households and jobs, it would have increased 50 percent. Due in large part to a shift to driving alone, daily vehicle trips in the Twin Cities area grew 88 percent between 1970 and 1990. Households own more cars than they once did, more people have become licensed drivers, and people are choosing to drive alone more and more. This is especially true of work trips. The work trip is repetitive, and most people make it as short as possible. Travelers wish to control their arrival time and not be dependent on others. This encourages people to take their own cars and guarantee themselves reliability and timeliness. Of all work trips taken in 1990, 80 percent were people driving alone. This compares to 61.2 percent in 1970 (see Figure 37 and Table 24, below). Travel Time and Distance Given a major regional increase in travel, and the physical growth of the metropolitan area, it is surprising that average travel times have actually declined since 1970. As average trip distances have increased because of large-scale suburban growth, which also spreads out points of travel origin and destination. Figure 38 compares trip duration and distance for transit passengers and auto drivers for all trips and work trips. Except for auto drivers going to work, reported travel time averages have decreased. Because people are driving further the time decrease indicates that the actual trip is being made at better average speeds. The overall increase in average vehicle trip distance from 5.09 miles to 6.55 miles between 1970 and 1990 has had a very significant impact on traffic. Coupled with the shift to driving alone, the increase in distance of trips has further multiplied the effect on travel of population increase alone. Click HERE for graphic. 60 Travel Behavior The Future of Mobility This discussion of changing trip rates, mode choice and trip distance has, to this point only served to illustrate why it is so challenging to develop accurate means to forecast the demand for travel. Each causative factor discussed above multiplies the effect of a basic increase in the number of travelers. As the population increases to 2.7 million or more residents in the next century, will travel continue to grow faster or slower than the number of potential travelers? Click HERE for graphic. The travel multiplication effect is one of the single most important lessons of the 1990 TBI. It was known to be operating but had not been quantified prior to the availability of the TBI information. In an attempt to picture the multiplier effect, the calculated impact of each factor is shown in Figure 39. Each line on the graph is drawn so as to indicate the increase above the lower line the at can be attributed to each factor operating by itself. The end impact of the travel multiplication effect is the total number of vehicle-miles traveled. Vehicle-miles traveled is the major 62 Summary Report demand-side indicator of how much highway "supply" in terms of lanes is required. Figure 39 shows that simple population increase alone between 1970 and 1990 would have increased travel demand to approximately 31 million vehicle miles by 1990. In fact, vehicle-miles traveled increased to 55 million. The other contributing factors were increases in trip-making per capita, drive-alone trips and trip distances. Vehicle-miles traveled, along with bus miles operated by the Metropolitan Transit Commission, are two of the most significant indicators of total demand for transportation services in the future. Both increased significantly in the past 20 years in response to the combination of more travelers, more travel and increased trip distances. For highways, there was the added factor of more drive-alone trips. In the future, it is probable that additional shifts in these factors will cause corresponding multiplier effects. Some will be greater than others. The probabilities are these: Population - The Council predicts that population will increase from 2.3 million in 1990 to nearly 2.8 million by 2010. If current conditions hold constant, the increase in vehicle-miles traveled would be about 10 million daily miles. Transit patronage should also increase. Click HERE for graphic. Trip Rates - Because household trip rates are more stable than per-capita rates, and because the decline in household size has slowed down, trip rates may stabilize in the coming decade. This factor could be monitored during the 1990s with small sample phone interviews. Any further increase in trip rates of zero-car or one- car households would also add transit travel. Auto Occupancy - Because work-trip auto occupancies are approaching 1.0 (in 1990 they were 1.08), it is also likely that this trend is flattening out. The rate of increase of drive-alone trips should slow down. Trip Length - Increased trip length added 20 percent to the total additional vehicle-miles traveled from 1970 to 1990. Trip length seems to correlate with urban sprawl. To the extent that suburban and exurban growth continues, trip length increase can be expected to follow. As the trip lengths in these areas are already up to 50 percent greater than in the central cities and developed suburbs, this factor alone may fuel a continued explosion of total vehicle-miles traveled. Click HERE for graphic. 63 Travel Behavior Click HERE for graphic. Summary Report APPENDICES Appendix A--Acknowledgements The 1990 TBI surveys were designed, coordinated and carried out with assistance from a number of agencies and a team of consultants. The following participated in the 1990 TBI: Strgar, Roscoe, Fausch, Inc. Transportation Advisory Board Barton Aschman Associates Inc. Minnesota Department of Jobs and Training Parsons, Brinkerhoff and Douglas, Inc. Minnesota Department of Transportation Douglas and Douglas, Inc. Robert McDowell Comsis Inc. Minneapolis Department of Traffic Engineering Richard H. Pratt, Consultant Inc. Downtown Council of Minneapolis Evaluation and Training Institute of Los Angeles, CA St. Paul Department of Public Works Colle & McVoy, Inc. Metropolitan Airports Commission Rockwood Research, Inc. Regional Transit Board MARKHURD Metropolitan Transit Council Anderson Niebuhr & Associates, Inc. Metropolitan Transit Commission N. K. Friedricks and Associates, Inc. University of Minnesota Office of Planning C. J. Olson Market Research, Inc. 65 Travel Behavior Appendix B--Revised Zones and Networks 1990 Highway Network and Traffic Assignment Zone Documentation Two large projects of the TBI were to redesign the Traffic Assignment Zones (TAZs), and rebuild the data set which represents the highway. network. The Minnesota Department of Transportation (MN/DOT) was charged with both of these eforts. The TAZs are used in the traffic modeling process as the common geographic unit for data summary. The system of TAZs covers the entire seven-county, Twin Cities metropolitan area. All home- interview data and selected other trip and socioeconomic data are compiled by TAZ. In addition, the TAZ system forms the geographic framework for coding highway and transit networks. Each TAZ is linked to all others by the highway network. Most are linked to one another by the transit network. The most significant application of the TAZ is as the geographic unit used by the models to predict attractions and productions of person-trips. A good example of a TAZ is a shopping mall. A mall has a homogeneous commercial land use that attracts people to work or shop. On the other hand, a residential suburban TAZ produces person-trips generated in proportion to the number of households, the type of household, and an income variable, such as the number of automobiles that each household has available on a daily basis for trip-making. The old TAZ system was designed around 1970 and was itself an extension and expansion of the original system developed for the 1958 TBI. Since 1970, a tremendous amount of land has been developed and the old zone system did not reflect these changes. Consequently, a new zone system was proposed by MN/DOT and reviewed by the Metropolitan Council, the seven counties and many of the local city planners. The review process was essential to the success of the new system. Many changes to the zones were recommended by the people most familiar with their area-the city and county planners and engineers. The 1990 zone system consists of 1,165 internal zones and 35 external stations. Internal zone boundaries most often lie along major highways or arterial streets or on any other significant physical boundary that shapes and directs trip movements, such as a large lake or major river. County boundaries also form edges of zones where appropriate. An external station is a point at the edge of the seven-county area where vehicle/transit trips leave or enter the metro system without being associated with the local land use. In other words, one end of the trip is outside our seven- county area. The 1990 zone system differs significantly from the 1970 system. Specifically, many zones were eliminated from Minneapolis and St. Paul and redistributed to the suburban cities. For example, Minneapolis dropped from. 225 to 125 zones, and Eden Prairie increased from 7 to 35 zones. Again, this is because of land-use changes between 1970 and 1990 and the expectation that changes in the future will most likely occur in the suburban areas. Maps of TAZs are available from MN/DOT Traffic Forecasting Section or the Metropolitan Council Transportation Division. The highway network, like the TAZ system, was out of date and structurally inconsistent. When assignments were made the trips loading onto the network 66 Summary Report were too many when the zones were very large. In other cases the trips were coming on at illogical locations. Consequently, it was decided to completely rebuild the network to coincide with the new zone system. The rebuilding of the 1990 highway network was completed by MN/DOT with input from the Metropolitan Council, the seven counties and local cities. In general, the work was done by MN/DOT and then reviewed and corrected by the other agencies. The criteria for the network rebuilding process were the following: - Compatible with new zone system - Compatible with mainframe (PLANPAC) and Micro computer programs TRANPLAN, EMME2) - Include all major and minor roads with Average Annual Daily Traffic (AADT) numbers greater than 1,000 - Coded by design inside 1-694, 1-494 ring - Compatible with MN/DOT's cartographic street series map The process of building the 1990 highway network started with Mn/DOTs "50 Series" maps. These are 1:24000 scale maps maintained and updated annually by MN/DOT that show all metro area streets and highways as well as water and political boundaries. This map series is the basis for a coordinated Geographic Information System (GIS) base map being developed by MN/DOT and the Metropolitan Council that incorporates 1990 census TIGER file geography. (TIGER is the U.S. Census Bureau's trademark for the Topologically Integrated Geographic Encoding and Referencing system.) The entire map series is fully digitized and runs on Intergraph Corporation's GIS software systems. At the Council the system runs on ARC/INFO software. To build the network, the line elements were extracted that represented interstate highways and ramps, U.S. highways, state highways, county roads, and county state aid highways. These roads were plotted on a base map with AADT numbers alongside them. Roads with less than 1,000 AADT were eliminated. City streets with more than 1,000 AADT were added. This provided a base highway network. Next, the zone centroid locations and centroid connectors were added to the computer file. The centroid locations were identified by locating the zones on aerial photographs and approximating the center of activity as represented by developed land or other significant features on the photo. Centroid connectors were added manually at this time by observing logical highway access to the zones. A minimum of four connectors were used to connect a centroid to the highway network. Using Intergraph's GIS software and several custom programs written by MN/DOT, the base network was numbered, and from-node, to-node and distance along the link were extracted. In addition, a number of default values were extracted at this time. For example, a road that was digitized as an interstate defaulted to a freeway facility type with two lanes. These default values were later corrected by plotting the attribute data in color and manually reviewing the system plots. To reflect some key parameters for transportation modeling, such as typical speeds by location in the region, the network links are related to geographical areas 67 Travel Behavior termed areatypes. The designated areatypes for these model parameters area Rural, Developing, Developed, Center City, Central Business District (St. Paul and Minneapolis CBD) and Outlying Business Area. Rural is defined as areas with population density less than one-person-per-acre. The Developing area is population greater than one-person-per-acre and outside the Interstate-694/Interstate- 494 (I-694/I-494) ring. Inside the I-694/I-494 ring is the Developed area. The Center City is described as Minneapolis and St Paul. The Central Business Districts are Minneapolis CBD and St Paul CBD. Outlying Business Centers are freestanding areas some distance from Minneapolis and St Paul which operate like a CBD. An areatype map is available from the Metro Council or Mn/DOT. Areas are used to create a matrix of areatypes by facility type. Facility types are categories of roads which operate in a similar manner. Our facility types are: 1. Metered Freeway 6. Undivided Arterial 2. Unmetered Freeway 7. Collector 3. Metered Ramp 8. HOV 4. Unmetered Ramp 9. Centroid Connector 5. Divided Arterial 10. HOV Ramp A metered freeway is defined as a facility operating with controlled access at all intersections on which all on-ramps for at least two miles are metered. An unmetered freeway has controlled access but on-ramps are not metered. Metered and unmetered ramps simply indicate the existence of a meter on the ramp. A divided arterial is a multi-lane facility divided by a physical barrier with the intersections controlled by signal lights. An undivided arterial has signals at the intersections but no physical divide between the lanes. It can be one or more lanes per direction. A collector is an undivided roadway with access controlled by stop signs. An HOV facility is described as a freeway-type facility restricted to use by multi-occupant vehicles. An HOV ramp is a ramp which connects to an HOV facility on one end of the link. Vehicles using HOV or HOV ramps must have two or more persons in the vehicle. A centroid connector is a hypothetical link that connects the regional highway network to a zone centroid. Up to four connectors are used to represent all the roads entering or leaving a traffic zone. The purpose of using connectors is to simplify the network. For example, in the Minneapolis and St. Paul area we would have to add thousands and thousands of city streets to the network to represent all possible paths. Instead, using connectors allows us to eliminate a large proportion of the streets and still accurately represent regional travel. The GIS software was used to create default speed and capacity values for all the network links. In this process, areatype polygons are created that automatically identify all the links inside of the polygon. The areatype value is automatically assigned to the link. The relational database software, ORACLE, is used to assign or update speed and capacity of links based on their areatype/facility type. Table 1 illustrates the speed matrix used to update the link speed record values for daily speeds. For example, a divided arterial (50 miles per hour, or MPH) in the Rural 68 Summary Report Area is faster than a divided arterial (37 MPH) in the Center City. Table 2 illustrates the speed matrix used to update link speed values for the peak period. Click HERE for graphic. Click HERE for graphic. 69 Travel Behavior Click HERE for graphic. Table 3 illustrates the capacity of the facility types in the model. The capacity is listed as per-lane-per-hour. Total hourly link capacity is the hourly lane capacity multiplied by the number of lanes on the link. Once speed and capacity were put in, the next task was to evaluate tree paths of the network. A tree path is the set of links used by the assignment model to route automobile trips from one zone to all the other zones in the system. MN/DOT personnel evaluated 16 different tree-path sets. Eight of the paths were internal zones and eight paths were external stations. The following list details the zones evaluated: EXTERNAL STATIONS INTERNAL ZONES I-94 East Downtown St. Paul I-94 West Downtown Minneapolis I-35 North Airport I-35 South Ridgedale Trunk Highway - 12 West Rosedale Trunk Highway - 169 South Woodbury (I-94 at I-694) Trunk Highway - 61 South Plymouth (I-494 at I-394) Trunk Highway - 65 North Mall of America 70 Summary Report Analyzing the tree paths was done by linking the GIS software with the transportation planning software TRANPLAN and PLANPAC. Special programs developed which reformatted the path reports into a-node and b-node pairs. These pairs of nodes, or unique node identifiers, were loaded into a table in ORACLE. Then, using a relational join, the link table tree variable was set to "Y" whenever the pair of node I.D.s in the two tables equaled each other. Then GIS was used create a map of the links in which the tree variable was set to "y." This unique approach proved to be very useful in locating errors in the network. The analyst could see a map of the tree and with very little efort determine which were being used (or not used) in the path. Some of the errors found were: one-way links coded backwards; links missing information; links with incorrect information. All the errors in the network were due to manual updates/coding of information. Table 4 describes the facility types, their assignment group code in the model, their number of network links and the total number of miles of each group. For example, metered freeways are coded as assignment group 1. There are 294 links coded as a metered freeway for a total of 115 center line miles. Table 4 1990 Network Statistics Facility Type Center Line Facility Type Assignment Group Code Number of Links Miles Metered Freeway 1 294 115 Unmetered Freeway 2 972 463 Metered Ramp 3 179 36 Unmetered Ramp 4 1,049 214 Divided Arterial 5 1,255 482 Undivided Arterial 6 3,236 2,151 Collector 7 1,838 603 Centroid Connector 8 2,742 1,181 HOV 9 27 8 HOV Ramp 0 8 2 Total 11,598 5,255 Travel Behavior Table 5 describes the area types, their code in the model, the number of network links in that area type and the total number of miles of network in that area type. MN/DOT and the Council have agreed that the network is to be maintained by the state traffic forecast engineer. Any questions about the highway network, its distribution, methodologies or capabilities should be directed to MN/DOT, at 296-0217. Table 5 1990 Network Statistics Area Type Center Line Area Type Area Type Code Number of Links Miles Rural 1 1,096 1,506 Developing 2 2,837 1,476 Developed 3 3,079 1,086 Minneapolis 4 1,490 401 Saint Paul 5 1,212 332 Minneapolis CBD 6 279 34 Saint Paul CBD 7 145 11 Outlying Business District 8 1,460 409 Total 11,598 5,255 72
