FHWA-HRT-24-017

HRSO-20/12-23(50)E

Cover Image: 

© 2023 Adobestock.com/R3nder. 

Modifications by FHWA to add color. 

Suggested print specifications: 

8.5 inches by 14 inches (roll fold brochure).

Recommended citation: Federal Highway 

Administration, Highway Safety Information 

System (Washington, DC: 2023) 

https://doi.org/10.21949/1521906

The Essential Analysis 

Resource for Making 

Informed Safety Decisions

Federal Highway Administration 

Office of Safety Research and Development 

Turner-Fairbank Highway Research Center

6300 Georgetown Pike

McLean, VA 22101

SAFETY DATA IN ONE LOCATION

HSIS supports highway safety analysis by enabling users 

to identify problems, examine the size and extent of a 

particular problem, and create design models that help 

predict potential future problems in a given roadway.

HSIS LABORATORY

As a virtual laboratory at the Turner-Fairbank 

Highway Research Center, the HSIS Laboratory 

uses state-of-the-practice statistical and virtual 

collaboration software to provide researchers and 

educators high-quality safety data, including linked 

roadway, traffic, and crash datasets. 

To support users, HSIS Laboratory staff members 

provide ongoing data interpretation help, combine 

files (including defining and interpreting file 

components and layouts), and merge data from crash 

and other files as needed. Additionally, they can 

help users analyze data from the Fatality Analysis 

Reporting System and National Automotive 

Sampling System, such as the General Estimates 

Sampling System and Crash Report Sampling 

System, and use GIS-based safety analysis tools.(5,6)

GUIDEBOOKS

Guidebooks for each HSIS agency are available 

to help analysts and programmers use HSIS. Each 

unique guidebook describes the agency’s data 

system and displays an alphabetized listing of 

all available variables along with their category 

and quality. The guidebooks are available in PDF 

format on the HSIS website.(1)

DATA ELEMENT TABLES

HSIS also maintains data element tables for all the 

agencies. The tables list the crash- and roadway-related 

variables side by side for all agencies. These tables 

enable data requesters to compare the availability of 

variables between specific agencies and can be 

accessed through the HSIS website.(3)

HSIS SUMMARY REPORTS

HSIS data are used in a wide variety of research 

efforts. Results from these efforts are documented 

in HSIS summary reports. To obtain copies of these 

reports, visit the HSIS website (https://highways.dot.

gov/research/safety/hsis).(1)

REFERENCES

1. FHWA. n.d. “Highway Safety Information System 

(HSIS)” (website). https://highways.dot.gov/research/

safety/hsis, last accessed November 7, 2023.

2. FHWA. 2023. “Participating States” (web page). https://

highways.dot.gov/research/safety/hsis/participatingstates, last accessed November 7, 2023.

3. FHWA. 2023. “Data” (web page). https://highways.

dot.gov/research/safety/hsis/data, last accessed 

November 7, 2023.

4. Cody, R. P. 1997. Applied Statistics and the SAS 

Programming Language. Upper Saddle River, NJ: 

Prentice Hall.

5. U.S. Department of Transportation. n.d. “Fatality 

Analysis Reporting System (FARS)” (web page). https://

www.nhtsa.gov/research-data/fatality-analysis-reportingsystem-fars, last accessed November 16, 2023.

6. U.S. Department of Transportation. n.d. “National 

Automotive Sampling System” (web page). https://

www.nhtsa.gov/crash-data-systems/national-automotivesampling-system, last accessed November 16, 2023.

Source: FHWA.

Ana Maria Eigen, D.Sc.

Phone: (202) 493-3168

ana.eigen@dot.gov

Carol H. Tan, Ph.D.

Phone: (202) 493-3315

carol.tan@dot.gov

FOR MORE INFORMATION

The HSIS website contains links to HSIS products, such 

as summary reports, safety analysis tools, and various data 

request tools.

https://highways.dot.gov/

research/safety/hsis/(1)

VISIT HSIS WEBSITE
HSIS PARTICIPATING AGENCIES

In 1987, five States were chosen for HSIS: Illinois, 

Maine, Michigan, Minnesota, and Utah.(2) Michigan 

stopped participating in 1997 and Utah in 2000 

due to changes in inventory data collection.(2) The 

primary criteria for State selections were data 

availability (the range of data variables collected), 

quantity, and quality.(2)

In 1995, California, North Carolina, and Washington 

were added to increase the available data and to 

provide better geographic coverage.(2) Charlotte, NC, 

joined in early 2011 to add urban area data.(2)

The HSIS relational database contains basic crash, 

roadway inventory, and traffic volume files from 

these eight agencies.(3) The database also includes 

information from some agencies about highway 

intersections, interchanges, lighting, and curves/

grades.(3) Additionally, some agencies provide 

supplementary datasets for vulnerable road user 

infrastructure, such as sidewalks, greenways, and 

transit stops.(3) Table 1 details the information available 

from each of the currently participating agencies.

DATA FORMAT

Data can be extracted in various 

formats, including comma-separated 

values, spreadsheets, SAS, geographic 

information system (GIS) shapefiles, and 

geodatabases.(4)

 The data can be acquired 

by filling out a data request form on the 

HSIS website.(3)

FILE TYPES

• Roadway files contain details about

road sections, including lane count,

lane and median widths, shoulder

width, urban or rural classification,

and functional categorization.

• Crash files contain individual case

information about crashes, including

collision type, involved vehicle

types, occupant demographics, fixed

object impacts, crash severity, and

weather conditions.

• Vehicle and other road user files

describe the vehicle-related

characteristics and other general

road user information (e.g.,

motorcycle, bicycle).

• Person files contain personal

information about individuals

involved in crashes, such as

demographics and physical

condition during the incident.

• Intersection files provide information

about traffic control methods,

intersection types, median and

shoulder types, and lane numbers.

• Interchange files include interchange

types and ramp characteristics.

• Horizontal curve/grade files contain

data on horizontal curves and vertical

grades, including degree of curve,

curve length, and grade percentage.

Many elements ensure the safety of our 

highways, from program policy decisions to 

roadway and traffic design. To assist safety 

analysts, researchers, and others involved 

in the study of highway safety, the Federal 

Highway Administration (FHWA) operates 

and maintains the Highway Safety Information 

System (HSIS).

HSIS provides quality data on many variables, 

including crashes, roadway, and traffic. Those 

data are acquired annually from a select group 

of States and one municipality, processed into 

a standard computer format, documented, and 

prepared for analysis.

HSIS supports the FHWA safety research 

program and provides input for program 

policy decisions. HSIS is also available to 

professionals conducting research under 

the National Cooperative Highway Research 

Program, universities, and others studying 

highway safety.

Agency First 

Year 

Average 

Crashes 

per Year 

Available

Roadway 

Mileage 

Available

California 1991 170,000 16,600

Illinois 1985 294,000 75,200

Maine 1985 32,000 23,500

Minnesota 1985 80,000 52,800

North 

Carolina 1990 361,000 48,800

Ohio 1997 280,000 66,200

Washington 1993 110,000 15,500

Charlotte 2004 34,000 5,200

Table 2. 

Data characteristics for participating agencies.(3)

Data File Type CLT CA IL ME MN NC OH WA

Roadway        

Crash        

Vehicle and 

other 

road users

       

Person  −      

Intersection   −     −

Bicycle/

pedestrian  − − − − −  −

Transit  − − − − − − −

Railroad line  − − − − − − −

Interchange −  −    − − Horizontal 

curve − − − −    

Grade − − − − − − − 

Lighting − − − −  −  − Roadside 

barrier − − − −  −  −

Table 1. 

Data files available from participating agencies.(3)

− No data. CLT = Charlotte, NC.

• Lighting, roadside barrier, and sign

support files detail the presence and types

of these supporting elements throughout

the road network.

• Bicycle/pedestrian infrastructure and

transit files offer insights into the

infrastructure for vulnerable road users.

All data are derived from police-reported 

crash records, maintained highway records, 

and other supplementary inventories. Table 2 

contains summary characteristics.
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