This document presents a synthesis of current information and operating practices related to roadside safety and is developed in metric units. The roadside is defined as that area beyond the traveled way (driving lanes) and the shoulder (if any) of the roadway itself. The focus of this guide is on safety treatments that minimize the likelihood of serious injuries when a driver runs off the road. This guide replaces the 1989 AASHTO "Roadside Design Guide."

A replacement to the publication entitled 'Highway design and operational practices related to highway safety', also known as 'The Yellow Book', and most recently published in 1974.

"The Highway Safety Manual (HSM) is a resource that provides safety knowledge and tools in a useful form to facilitate improved decision making based on safety performance. The focus of the HSM is to provide quantitative information for decision making. The HSM assembles currently available information and methodologies on measuring, estimating and evaluating roadways in terms of crash frequency (number of crashes per year) and crash severity (level of injuries due to crashes). The HSM presents tools and methodologies for consideration of 'safety' across the range of highway activities: planning, programming, project development, construction, operations, and maintenance. The purpose of this is to convey present knowledge regarding highway safety information for use by a broad array of transportation professionals"--p. xxiii, vol. 1.

Committee Serial No. 90-21. Profusely illustrated with photographs of highway safety hazards and automobile accidents.