TABLE OF CONTENTS Roger L. Brockenbrough, P.E.
President
R. L. Brockenbrough & Associates, Inc.
Pittsburgh, Pennsylvania
One of the most important and most challenging aspects of highway engineering is designing to enhance life safety. This chapter focuses on roadside safety, which encompasses the safety of vehicles that leave the roadway and shoulder.
This material is based largely on the publication of the American Association of State Highway and Transportation Officials (AASHTO), Roadside Design Guide (2002), which was developed by the AASHTO Subcommittee on Design, Task Force for Roadside Safety, currently under the chairmanship of David L. Little, P.E. Made up of about 25 highway engineers with diverse experience, the task force maintains and updates a synthesis of current information and operating practices to serve as a comprehensive guide to individuals and agencies in developing standards and policies. Their contribution to promoting highway safety is gratefully acknowledged.
The roadside is defined as that area beyond the traveled way and shoulder. Thus, roadside safety is concerned with treatments that minimize the likelihood of serious injuries when a vehicle runs off the roadway.
Roadside safety design has received particular emphasis over the last 30 years or so. The increased awareness of its importance and the development of improved safety concepts and devices have contributed significantly to improved safety. As shown in Fig. 6.1, the traffic fatality rate expressed in terms of driven distance has declined to one-third of that in the mid-1960s. Many factors have contributed to the...
