Summary Report Index
HSIS - Highway Safety Information SystemThe Need:
Highway engineers and administrators are continually faced with decisions concerning the design and operation of the highway system. An important part of the decision-making process is the potential impact on the safety of the highway users. Informed decision-making requires an understanding of how safety is affected by the geometric design of the roadway, the selection and placement of roadside hardware, the use of traffic control measures, the size and performance capabilities of the vehicles, and the needs and abilities of the users. This understanding can be developed through sound analysis of information about accidents, roadway geometrics, traffic control devices, traffic volume data, and the location of hardware and obstacles on the roadside. These data must be present in computerized files and easily linked so that data can be rapidly assembled and prepared for analysis.
A Solution: HSIS
The Federal Highway Administration (FHWA) has developed a highway safety data base that can meet this need -- the Highway Safety Information System (HSIS).
The HSIS uses data already being collected by States for the management of the highway system, for the study of highway safety. The HSIS is a roadway-based system which provides quality data on a large number of accident, roadway, and traffic variables. The data are acquired annually from a select group of States, processed into a common computer format, documented, and prepared for analysis.
The HSIS can be used to analyze a large number of safety problems. They can range from the more basic "problem identification" issues to identify the size and extent of a safety problem to modeling efforts that attempt to predict future accidents from roadway characteristics and traffic factors.
The HSIS is used in support of the FHWA safety research program and as input to program and policy decisions. The HSIS is also available to analysts conducting research under the National Cooperative Highway Research Program, university researchers, and others involved in the study of highway safety.
The Highway Safety Information System
Participating States
In 1987, five States were chosen to be included in the HSIS: Illinois, Maine, Michigan, Minnesota, and Utah. The primary criteria used in selecting the states were the data availability (the range of data variables collected), quantity, and quality. In 1995, California, North Carolina, and Washington, were added to increase the amount of data available and provide better geographic coverage.
Data Files
All of the selected States maintain basic crash files, roadway inventory files, and traffic files. In addition, individual states also collect other types of data. Depending on the particular problem being studied, files from one or more States may be used by the analyst. The following table indicates the files that are available.
CA IL ME MI MN NC UT WA Crash X X X X X X X X Roadway X X X X X X X X Traffic Volume X X X X X X X X Curve and Grade X X X X VIN X X X X Intersection X X X Interchange/Ramp X X X X X Crash - Contains basic accident, vehicle, and occupant information on a case-by-case basis. Typical data includes type of accident, types of vehicle, sex and age of occupants, fixed object struck, accident severity, and weather conditions.
Roadway Inventory - Contains information on roadway cross-section, types of roadway and other roadway characteristics. Data includes the number of lanes, lane width, shoulder width and type, median width, rural/urban designation, and functional classification.
Traffic Volume - Contains Annual Average Daily Traffic (AADT) data. Additional data on hourly volumes and percent trucks is also available in selected States and/or locations.
Roadway Geometrics - Contains horizontal curve and vertical grade information. Data includes degree of curve, length of curve, percent grade.
Intersection - Contains information on highway intersections. Data includes traffic control type, intersection type, signal phasing, and turn lanes.
Interchange - Contains information on highway interchanges. Data includes interchange type and ramp characteristics.
Vehicle Identification Number (VIN) - Contains VIN data decoded using the VINDICATOR program. Data includes make and model, body style, body type, curb weight, and wheelbase.
Guardrail/Barrier - Contains an inventory of guardrail. Data include guardrail type, post type, rail height, and terminal type.
Data Format
All of the data files are stored in the SYBASE relational database. Data can be extracted in an ASCII format or converted to Statistical Analysis System (SAS) format for use in analysis. Data can be provided via different mediums. Currently we provide data on floppy diskettes, 8 mm tapes, CD-ROM, Optical disk, FTP, E-mail and spread sheet format. The data can be requested by filling out HSIS data request form.
Data Quantity
The HSIS contains only police reported accident data on the state-maintained highway system. The size of the state-maintained system depends on the policies of the State and is not necessarily proportional to the size of the State. Data for the original five HSIS States is available from 1985 while data for the three new HSIS States is available from 1991. The following table provides an indication of the quantity of data available.
First Year Available Average Crashes/Year Roadway Mileage California 1991 45,000 7,000 Illinois 1985 150,000 16,000 Maine 1985 39,000 22,000 Michigan 1985 140,000 9,600 Minnesota 1985 85,000 49,600 North Carolina 1991 118,000 31,000 Utah 1985 50,000 12,900 Washington 1991 34,000 8,600 The Guidebooks
Detailed guidebooks for each HSIS State are available to HSIS users. The purpose of the guidebooks is to provide sufficient information for both the analyst and the programmer to effectively use the system. The guidebooks document data quality issues uncovered through annual quality control checks or reported by system users. The guidebook for each State consists of two volumes. Volume I contains a basic description of the State data system, an alphabetized listing (by file type) of all available variables, detailed definitions of each category present within each variable, and notes on the quality of the variable. Volume II contains single variable tabulations for a large number of "key" variables within each of the files. The tables include data for the previous five years. The HSIS guidebooks are updated on a two-year cycle.
The Generic Variable Tables
Besides the Volume I and Volume II of the guidebooks for all States, a set of two generic variable tables have been developed for all the States. The first table lists the crash related variables for each State side-by-side and the second table lists the roadway related variables. The purpose of developing these tables was to give the ability to HSIS data requester to compare between States the availability of variables.
Before viewing the tables, please read the directions for using the tables.
View Table 1 - For Accident, Vehicle, and Occupant Files
View Table 2 - For Roadway and Roadway Related FilesThe HSIS Laboratory
The HSIS is operated by the >University of North Carolina Highway Safety Research Center (HSRC) and LENDIS Corporation, under contract with FHWA. The HSRC and LENDIS staff conducts research with the HSIS and provides guidance to users on the application of the HSIS for the study of highway safety problems. The LENDIS Corporation is also responsible for the operation of the HSIS Laboratory at the FHWA’s Turner-Fairbank Highway Research Center in McLean, Virginia. The HSIS Laboratory contains a variety of computer hardware and software including:
PCS and Workstations - to store, maintain, and analyze HSIS data. HSRC and LENDIS staff, FHWA staff, and visiting researchers can access the HSIS files, extract pertinent data, and conduct analysis using the latest computer hardware and statistical analysis software.
Videodisc Photologs - to access roadway images for selected HSIS States. The videodisc photologs allow on-site users to quickly access images for visual verification of existing data and/or collection of supplemental data. Currently, coverage includes the Michigan, Minnesota, Utah, Washington and California state-maintained highway systems. Additional States will be added as the photologs become available.
Geographic Information Systems (GIS) - to manipulate and display HSIS data. Several GIS software packages are available for use in analyzing HSIS data. The HSIS laboratory provides support for the development and testing of GIS-based safety applications, resulting from other FHWA-funded efforts.
Since its inception the HSIS has been used in a wide variety of research efforts. Significant results from these efforts are documented in 2 to 4 page HSIS Summary Reports. Hard copies are available by calling the HSIS Report Center at (202) 493-3464.
For more information contact:
Michael S. Griffith
Federal Highway Administration
Office of Safety R&D
6300 Georgetown Pike, T-303
McLean, Virginia 22101-2296
(202) 493-3316SYSTEM TOOLS - This area is still under development.
DATA REQUEST
(To request HSIS data, click here)