Turner-Fairbank Highway Research Center

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Investigation of National Highway System Roadways in the HSIS States

Product Type

HSIS Summary Report


Charles V. Zegeer, Herman F. Huang, J. Richard Stewart, and Carolyn Williams




Motor vehicle crash rates and roadway characteristics for National Highway System (NHS) and non-NHS roads in seven states-California, Illinois, Maine, Michigan, Minnesota, North Carolina, and Washington-are presented. Crash and roadway data were extracted from the Federal Highway Administration's Highway Safety Information System. Overall, crash rates on NHS roads were approximately 10 percent lower than those on non-NHS roads, perhaps the result of higher design standards. Crash rates on urban roadways were considerably higher than on the corresponding rural roadways in each state. For rural roadways, fixed object crash rates were higher on NHS roads. The distribution of crashes by severity was quite similar on NHS and non-NHS roads. The majority of NHS roads had lane widths of 3.4 m (11 ft) or more, and many had shoulder widths of 1.5 m (5 ft) or more.

Link To HSIS Summary Report

Investigation of National Highway System Roadways in the HSIS States


National Highway System
Crash Rate

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HSIS Summaries

HSIS Summary Reports are two to eight pages in length and include a brief description of the issue addressed, data used, methodology applied, significant results, and practical implications.

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Research Reports

A variety of research studies have been performed using data from HSIS. Many of the final reports prepared are now available electronically.

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Technical Summaries

Research reports are often summarized in executive summaries, technical briefs, or other abbreviated formats. Included here are those road safety summaries that involved research using HSIS data.

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Safety Analysis Tools

In addition to conducting research, HSIS resources are also used to develop products that can be used by practitioners in the analysis of safety problems.

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Other Projects

HSIS data are sometimes used in research studies that result in other types of finished products, such as dissertations, theses, and conference proceedings.

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