DOI

10.5703/1288284314298

Report Number

FHWA/IN/JTRP-2009/07

Abstract

The Indiana Department of Transportation (INDOT) has installed guardrail systems on interstate highways and other highways in accordance with a variety of standards throughout the years. Traffic volume has increased and the posted speeds have been raised on most INDOT’s interstate highways. Consequently, the characteristics of run-off-the-road (ROR) crashes may have changed. In the meantime, material prices have increased considerably and the guardrail maintenance and crash repair costs have increased accordingly. There is no doubt all these changes will not only greatly affect the ROR crash prediction, but also greatly affect the guardrail benefit/cost analysis. This study examined the current use of roadside guardrails on INDOT intestates, State highways, and US highways, roadways, including types and lengths of guardrails, types and numbers of guardrail end treatments, and field guardrail positions. Based on the records of total 4657 ROR crashes occurred in 2004 and 2006, this study investigated the characteristics of ROR crashes, such as frequencies and locations of ROR crashes, crash consequences (number of vehicles involved, injuries and fatalities), and the effects of main factors, in particular roadway geometrics, seasons and traffic volume, on the highways of different classes. Furthermore, this study investigated the features of vehicle-guardrail crashes, including impact positions and corresponding frequencies and consequences. ROR crash predictions were examined in all aspects in this study, including encroachment rates, crash probabilities, and severity probabilities. It was found that the encroachment rates obtained by this study are less than those in the AASHTO Roadside Design Guide.

This study evaluated the issues associated with the guardrail crash repair costs, such as parts costs, labor costs, and equipment costs. Guardrail steel parts prices increased dramatically. For guardrail terminal crash repairs, the majority of the repair costs were spent on parts. Hex-Foam Sandwich demonstrated the greatest repair cost per crash and ET 2000 Plus demonstrated the lowest repair cost per crash. The repair costs are overestimated for CAT, ET 2000 Plus, SKT 350 and Impact Barrel, but underestimated for other crash cushions in the INDOT Design Manual. Different from the guardrail terminal repairs, the labor rather than the parts consumed the majority of the repair costs for regular guardrail repairs. The average guardrail repair cost is $722 per crash that is less than the guardrail repair cost the INDOT Design Manual. The annual average guardrail maintenance cost is $0.305 per linear foot. ArcMap was utilized to develop an interface for effectively managing and analyzing guardrails and ROR crash data.

Keywords

Run-off-the-road crash, encroachment, guardrail, guardrail face, guardrail end treatment, crash cost, repair cost, maintenance cost, roadside safety data management, SPR-3028

SPR Number

3028

Project Number

C-36-64O

File Number

3-5-15

Performing Organization

Joint Transportation Research Program

Publisher Place

West Lafayette, Indiana

Date of this Version

12-2009