Citation

Miller H. ITE J. 1980; 50(11): 7 p..

Copyright

(Copyright © 1980, Institute of Transportation Engineers)

DOI

unavailable

PMID

unavailable

Abstract

Improvement strategies for reducing collisions with roadside fixed objects (curbs, guide railings, luminaire and sign supports, bridge piers and abutments, drainage structures, and steep slope sides) include eliminating the object, moving it longitudinally to a sheltered location, moving it laterally away from the roadway, or reducing the hazardous consequences of a collision (by flattening slopes, providing breakaway supports for signs, or installing impact attenuation devices). The cost-effectiveness technique for selecting the most efficient roadside improvement strategy is discussed and a "hazard model" is described which quantifies the accident potential of fixed objects. Glennon's hazard model (1974) is summarized, a calibration procedure is described, and specific problems in applying cost-effectiveness techniques to a design project are examined. It is noted that the use of "typicals," examples of frequently encountered conditions, saves time and effort when searching for the best safety alternative. Methods are recommended for restricting the number of alternatives which are carried into a design stage: use of "typicals," and establishing a minimum value on the change in hazard index and a maximum value on the cost-effectiveness ratio. Future research is recommended on other factors influencing the frequency of collisions with fixed objects: road curvature, pavement friction, speed, and multivehicle accidents which force a car off the roadway.