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Safety Applications of ITS in Rural Areas

1 Introduction

Traffic safety in rural areas continues to be a source of concern among the Nation’s highway users, and Intelligent Transportation Systems (ITS) could play a critical role in addressing this concern. ITS can be divided into vehicle-based systems and infrastructure-based systems. The focus of this report is on infrastructure-based systems.

This report describes the methodology and results of a nationwide synthesis of existing and planned technology applications aimed at improving safety in rural areas. Detailed information on the individual systems is provided, and an overall summary of the systems is presented. “Hot Spots” for deployment of ITS technologies aimed at improving safety in rural areas were identified by activity participants and are presented in the report.

In addition to providing information on the individual systems, the report identifies the population of crashes addressed by each technology category and the situations where deployment of such systems should have the greatest potential payoff in improving safety in rural areas.

While this report focuses on rural ITS safety applications, a companion report discussing ITS safety applications in metropolitan areas is also available from the Federal Highway Administration (FHWA).(1)

2 Information Gathering Methodology

The desired information for the report was collected using a questionnaire that was versatile enough to be used for a variety of types of systems. The FHWA Task Manager, who is quite knowledgeable about the Variable Speed Limit (VSL) System that was deployed in Albuquerque, New Mexico, piloted the questionnaire. The questions that made up the questionnaire were open ended. The people responding to the questions were not asked to select from a set of potential answers; rather, they were allowed to write their response in their own wording. The reason for this approach was that the purpose of the questionnaire was to gather information on these systems, not to statistically compare similarities and differences between the various systems.

The ITS specialists at each FHWA Division Office (with the exception of the District of Columbia office whose coverage area is entirely urban) were contacted, and the purpose of the study was described to them. They were then asked if there are any systems currently deployed in their State that would be of interest to the study. In order to qualify, the system had to be an ITS type system deployed in a rural area, and had to be aimed at reducing the frequency or severity of crashes. If the ITS specialist identified one or more appropriate systems, they were sent a questionnaire by either fax or email. Some of the specialists forwarded the questionnaires to their associated State Department of Transportation (DOT) for completion, or asked the research team to contact the State DOT directly.

Questionnaires were also sent to select domestic and international contacts with known experience with rural systems.

Topics covered by the questionnaire included:

A member of the research team provided the section on Animal Crash Warning Systems, and the information on Rail Grade Crossing systems was obtained from the literature and from personnel at the U.S. Department of Transportation Joint Program Office (JPO). Information on specialized work zone systems was obtained mostly from literature.

The research team also examined the target population of crashes for the various types of ITS applications encountered in this study. The approach taken to perform this task was to determine the number of annual fatal crashes that occurred under the conditions that the various ITS applications are designed to address. This was performed using Fatality Analysis Reporting System queries on 1998 data.(2 ) For the most part, rural ITS systems are aimed at preventing crashes in a specific area, and many are not necessarily appropriate for generalized application. However, by looking at the number of crashes that happen under the general conditions that the various systems are designed to address, we can get some idea of the maximum possible extent of the overall rural crash problem that a “perfect” system of a given type could potentially influence. This is not to say in any way that the systems studied here could prevent the entire number of crashes in the specific targeted crash population. It would not be reasonable to assume that any system could prevent the entire target population of crashes unless it removed the driver element from the equation. The crash numbers for a given set of conditions provide a target of the number of crashes that need to be prevented and provide us with a basis for comparison.

Fatal crashes will be the focus, since they are of primary concern in rural areas. Other crash severities are more of an urban problem than a rural problem. One thing that must be remembered though, is that the majority of these systems only provides advice or warnings. It is up to the driver whether or not he or she will follow the advice or heed the warning and adjust his or her driving behavior. Enforcement may also help play a role in convincing the driver to change his or her behavior appropriately.

The results of the information gathering exercise are presented in the following section. The individual systems were organized into categories, including:

Where appropriate, these categories were also broken down into a number of sub-categories. The targeted crash population is provided at the end of each system sub-category.

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