Barrier installations are warranted (or justified) only at highway locations where the consequence of an errant vehicle leaving the roadway is judged to be more hazardous than the impact with the barrier installation. A six degree-of-freedom mathematical model was found to be useful in describing dynamic behavior of a vehicle during impact. Predictions of vehicle and barrier behavior correlated with results obtained from full-scale crash tests. Crash conditions simulated with a computer were used to identify and evaluate vehicle static and dynamic as well as barrier parameters. Vehicle weight, yaw mass moment of inertia, and deformation constant were found to be significant.

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."

At head of title: National Cooperative Highway Research Program.

This roadside safety design package has been developed to satisfy a need for training in this area. It is hoped that all persons involved in the design, construction, operation, and maintenance of highways will become familiar with the concepts contained in the program. The concepts and practices discussed come from those contained in the AASHTO publication, "Highway Design and Operational Practices Related to Highway Safety". They are discussed in considerable depth in this program and should provide a good working knowledge of roadside safety design. Much of the program is oriented around freeways; however, the principles apply equally toward the lower order highway.

TCRP report 155 provides guidelines and descriptions for the design of various common types of light rail transit (LRT) track. The track structure types include ballasted track, direct fixation ("ballastless") track, and embedded track. The report considers the characteristics and interfaces of vehicle wheels and rail, tracks and wheel gauges, rail sections, alignments, speeds, and track moduli. The report includes chapters on vehicles, alignment, track structures, track components, special track work, aerial structures/bridges, corrosion control, noise and vibration, signals, traction power, and the integration of LRT track into urban streets.