National Transit Database Transportation Accessibility

Measure

Transportation Accessibility: Percent of the transit bus fleet that is accessible under the Americans with Disabilities Act of 1990 (ADA) (the proportion of the transit bus fleet that is lift- or ramp-equipped, measured in percent of total fleet)

Definition

This measure of ADA accessibility is a partial measure. It simply measures lifts and ramps on transit buses. The measure summarizes the availability transit buses in our national fleet that can accommodate wheel chairs through the use of mechanical lifts or ramps from the curb to the vehicle. Accessible vehicles under the ADA includes many things, not just wheel chair accessibility. For example, it would include communications equipment to help orient individuals with sensory impairments, such as vision or hearing. Many new transit vehicles have these on-board systems. It is important define what is being measured and what is not. Transit buses are buses used in urbanized areas to provide public transit service to the general public. Transit buses do not include private intercity buses (Greyhound), private shuttle buses, charter buses, or school buses.

Data Scope

At a transit authority, vehicle purchases are significant capital expenditures. Vehicles purchased with FTA funds must have a useful life of 12 years. Whether a bus is purchased or leased, the equipment on the bus is recorded, including lifts and ramps. For the last 20 years, transit agencies have reported on the equipment in their bus fleets to the FTA in their annual NTD submissions. There is a census of publicly funded transit buses in urbanized areas. It is not a sample. Urbanized areas have more than 50,000 persons, and are defined by the Census Department. By statute, every FTA formula grant recipient in an urbanized area must report to the NTD. In cities of this size, virtually every transit authority receives FTA funding. There are only a few cities of over 50,000 persons that do not provide public transit service. Publicly funded transit service can be directly operated or purchased transportation.

Performance Measure Sample Design

When urban transit authorities are allowed to report on their local fiscal year, there is no problem in obtaining bus fleet data. However, in transit, a problem exits in providing bus fleet data on a calendar year reporting period to meet the Government Performance and Results Act (GPRA) timeframe. About 200 of our 600 transit authorities are not ready to report prior year data by the end of January. To be more specific, not all of the 1999 NTD report year data will be submitted to FTA by February 2000, to use in FTA’s GPRA Performance Measures. Therefore, an estimate for 1999 ADA accessibility of the bus fleet will have to be made, using less than 100 percent of the data for 1999. Since the inception of the ADA in 1990, to get more current data on bus fleet accessibility, FTA has relied on a survey performed each year by the American Public Transit Association (APTA). APTA’s survey uses NTD data and survey data to estimate fleet accessibility.

APTA’s survey is comprised of 400 transit authorities, constituting about 90 percent of all transit service. FTA has used the APTA survey as a current estimate of transit bus fleet accessibility for over a decade. The estimate is made from a very representative, stratified sample that approximates the universe. The growth in the accessibility of the bus fleet has very stable, predictable series. The estimation method has been tested against final data from the NTD for many years. The estimate proved a very accurate predictor of the final NTD figure.

Data Collection

At a transit authority, the equipment on each bus, purchased or leased, is recorded, including lifts and ramps. For the last 20 years, transit agencies have reported on the equipment in their bus fleets to the FTA in their annual NTD submissions. There is a census of publicly funded transit buses in urbanized areas. Transit authorities also prepare fleet management plans. To meet GPRA Performance Measure timelines, the FTA will use the APTA survey as an estimate of final NTD data on fleet accessibility. APTA conducts annual survey of the transit bus fleet. APTA uses NTD data and fleet management plans in its surveys 400 of the 600 transit authorities. Over the last decade, APTA’s survey has produced excellent estimates of bus fleet accessibility. The estimate proved a very accurate predictor of the final NTD figure. For the Performance Measure estimate, about 90 percent of the bus fleet data for report year 1999 will have been collected by APTA.

Method - After the close of their local fiscal year, transit authorities produce annual reports, summarizing operating, fleet, and financial data. Under Federal requirements, financial reports must be audited. The data is also certified. The data in these reports are entered on to forms on a diskette submitted to the NTD. The data on this diskette must conform to the precise data definitions in the Reporting Manual for the NTD and the Uniform System of Accounts for the NTD. These data elements include bus fleet and accessibility data, indicating of the amount of accessible transit service made available to the public.

Schedule - Each year, the data on this diskette is submitted within four months of the close of the local fiscal year. Transit properties that use calendar year reporting submit their completed NTD diskettes in April. Of the 600 transit properties, over 400 will have been included in the APTA survey by January 2000. These reporters comprise 90 percent of all transit bus fleet data.

Response Rates - The NTD program is required by statute. For 20 years, the 600 transit operators in urbanized areas, with populations in excess of 50,000 persons, have filed annual reports to the NTD. Every FTA formula grant recipient must report to the NTD. Without an annual NTD submission, FTA grant funds are cut off. The response rate is about 100 percent. In cities of this size, virtually every public transit authority receives FTA funding. For this reason, the NTD is one of the more complete industry databases in the Federal government. For this sample estimate, 90 percent of total transit bus fleet data will have been included in the APTA survey.

Sampling Error

Sampling errors produce faulty estimates. In the NTD, other than passenger miles, annual data is actual data, not a sample estimate. Further, transit systems want to continue FTA funding, so they submit NTD data. Simply put, the universe is known. However, for the Performance Measures, the estimate of 1999 bus fleet accessibility will be based on 90 percent of all transit, which will have been included in the APTA survey by February 2000. Using data for the last decade, this method has been validated. This method has produced estimates with mean forecast errors of less than one percent. A sample based on 90 percent of actual bus fleet data for all transit approximates the universe. Many of the modal statistics that BTS and DOT use as a matter of routine are based on less than 90 percent of the universe. In this estimate, sampling errors are not a serious problem.

Nonsampling Error

Nonsampling errors are primarily a result of noncoverage errors. Data for tiny systems in urban areas and small systems in nonurban (rural) areas are not included in the NTD. Nonurban systems and operators with less than 10 vehicles in urban areas combined would add only a percent or two to total transit service nationwide.

Not all data errors are related to poor sampling techniques. Some errors are measurement or coding errors. Data may not be gathered from some groups. These errors are discussed in this section.

Nonentry Error or Missing Data - The NTD program is required by statute. Every FTA formula grant recipient must report to the NTD. Without an annual NTD submission, FTA grant funds are cut off. The response rate is near 100 percent. Fields that are left blank are returned to the transit agency along with a detailed review letter highlighting errors and omissions. However, a small percentage, less than one percent, of data is missing. Tiny transit authorities, with less than 10 vehicles, are exempt from having to complete certain forms. This could produce a nonentry on certain data elements for about 30 tiny systems. On a few occasions, a few months of operating data, not vehicle data, are lost when contractors are changed. For the GPRA estimates, about 10 percent of the bus fleet for 1999 will not have been reported because of local fiscal years, not missing data.

Duplicate Entry Error - The NTD program requires that services purchased by a transit authority be reported separately from directly operated service. This avoids the double counting problem. The data audit and certification requirements also help avoid redundancy. Few bus fleet reports involve more than one transit authority, reducing the chance for double counting.

Response/Measurement Error and Coding Errors - Measurement errors occur when incorrect data is provided. Coding errors occur when correct data is improperly recorded. NTD staff work hard to catch bad data and recording errors. First, transit authorities file NTD reports each year; the NTD is not a special study. Regular reporting reduces errors. Second, the data is audited and certified by local officials. Third, FTA validation analysts, familiar with this transit authority, use range checks for 1999 data against data from last year and previous years. Data fields are also checked for proper coding. Validation is discussed, below. Fourth, validation ratios and performance measures, such as operating costs per vehicle, vehicle miles per trip, are calculated. These ratios are compared to previous submissions and systems of similar size. Any significant variations are flagged and returned to the transit authority to explain or revise. This validation feedback loop is very important in producing accurate data for legislative apportionments is not a common feature of most industry databases run by the government.

Noncoverage Error - Noncoverage errors occur when members of the population are missing because they were not included in the sample. In the NTD, there are some noncoverage errors, but these errors are deminimus. First, as noted under missing data, certain tiny public transit authorities, with less than 10 vehicles, exist in urban areas. These small systems do not have to report the full NTD data. There are about 30 of these tiny systems accounting for less than one-half of one percent of total transit service. Second, there are a few public transit authorities, usually with very few vehicles, that do not receive FTA funds and do not report. However, most public transit authorities that do not receive FTA funds, voluntarily and regularly report to the NTD to increase the apportionment for their urbanized area. Third, the largest piece of missing data is public transit in rural areas, or nonurban areas with less than 50,000 persons. The States receive FTA funding to administer these programs. Because these systems are not direct FTA grant recipients, they do not submit data to the NTD. The NTD was not designed to capture this data. Nonurban systems, which usually use more vans than buses, would add only a percent or two to the total bus fleet nationwide.

Verification and Validation

To produce an accurate and equitable apportionment of FTA funds across the nation, the FTA has made a commitment of significant resources in our NTD detailed verification and validation feedback process. Intensive data validation efforts are not a common feature of most industry databases run by the government. In most industry databases, data is usually accepted as submitted. The NTD employs a number of exhaustive verification and validation efforts. First, transit authorities file NTD reports each year; the NTD is not a special study. Regular reporting increases consistency and reduces errors. Second, at the local transit level, the NTD diskette contains certain error checks. Third, prior to submission, the data is audited and certified. An independent auditor must complete an A-128 audit and signs off on the NTD submission. The agency’s CEO certifies the submission. Fourth, FTA validation contractors, familiar with this transit authority, use range checks for 1999 data against data from last year and previous years. Data fields are also checked for proper coding. Errors and inconsistencies are enumerated in a Detailed Review Letter (DRL) that is sent back to the submitting transit agency. DRL problems must be addressed and data revisions made for inclusion in the NTD. Failure to address validation or certification problems can result in loss of eligibility for FTA grants. Fifth, validation ratios and performance measures, such as costs per hour, miles per hour, are calculated. These ratios are compared to previous submissions and systems of similar size. These ratios check the internal consistency of the submission. Any significant inconsistencies are flagged and returned to the transit authority to explain or revise. The NTD contractor performs validation checks involving 200 calculations on each submission. This validation feedback loop is very important in producing accurate data for legislative apportionments and fixed-guideway allocations. For fleet data, APTA uses NTD data as the basis for their survey. Their survey simply updates the most recent NTD data. With the APTA survey, about 90 percent of the data for all of transit in 1999 will have been included in the Performance Measures estimate. For the last decade, this APTA measure has been an accurate predictor of the final NTD figure for bus fleet accessibility.