Date of Award

10-2010

Degree Name

MS in Civil and Environmental Engineering

Department

Civil and Environmental Engineering

Advisor

Anurag Pande, Ph.D.

Abstract

National and statewide (California) collision numbers are currently on the

decline; however, the U.S. is declining at a much slower rate than most other

developed countries, and in some aspects is actually regressing in terms of traffic

safety. Although state highway safety is improving, local roadway safety may

actually be regressing. Approximately three-quarters of all U.S. public roadways,

and approximately 80% of all injury accidents fall under the jurisdiction of cities.

However, cities may not be allocating the proper level of resources, or operating

under the proper administrative methodologies to adequately address these

safety issues.

This research finds that on average, California cities are experiencing

increasing annual collision rates. In particular, small cities with populations of

less than 25,000 are experiencing the largest increases, whereas larger cities are

experiencing static or slightly decreasing collision rates. California’s statewide

collision statistics and the administration surveys conducted as part of this study

indicate that there is a correlation between a city’s administrative

analysis/mitigation methodologies and their annual collision rate trends.

Specifically, cities with lower traffic engineering staff to population ratios tend to

have increasing collision rates, as opposed to cities with high staff to population

ratios, which have decreasing collision rates. Also, this research shows that cities

that allocate more traffic safety resources to enforcement over engineering tend

to have increasing collision rates, as opposed to cities allocating more resources

to engineering that have decreasing collision rates.

This research also finds that there are predominant and correctable

factors that lead to the various collision types. Cities that employ routine system

wide traffic safety audits addressing location-specific collision trends based on

these predominant factors tend to have decreasing collision rates, as opposed to

those that do not.

In general, collision rates among U.S. cities are increasing largely due to

increasing rates on roadways within the jurisdiction of smaller cities, most

commonly with populations under 25,000. Over one-third of cities are not staffed

at the proper levels, not allocating the necessary resources to traffic engineering

activities, and are not employing an adequate evaluation/mitigation strategy. The

findings of this study provide guidance and framework to cities for developing

effective traffic safety strategies by identifying the characteristics of those cities

that have been successful in reducing collision rates as examples. In particular

the value of this research is important for non-engineering administrative staff

and political bodies in terms of establishing appropriate staffing levels and

resource allocations necessary for an effective traffic safety program.

The findings of this study provide guidance and framework to cities for

developing effective traffic safety policy preference by identifying the

characteristics of those cities that have been successful in reducing collision

rates as examples. In particular this research is important for non-engineering

administrative staff and political bodies in terms of establishing appropriate

staffing levels and resource allocations necessary for a transportation

department to be effective in reducing traffic collisions and resulting damages.

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