Citation

O'neill B. Accid. Anal. Prev. 1977; 9(3): 157-165.

Copyright

(Copyright © 1977, Elsevier Publishing)

DOI

unavailable

PMID

unavailable

Abstract

An environmental safety improvement is one that would reduce accidents given fixed driver behavior. Drivers may respond to it by driving less carefully than before, however, thus diverting the improvement toward some non-safety goal such as quicker arrival at a destination. A model is given in which the driver is assumed to be rational, that is, to maximize the total expected value of his ends. An expression is derived for predicting the direction of change of the accident rate in response to the environmental safety improvement.In a model of rational speed choice, the direction of change of the accident rate depends on the shape of the functions relating speed and accident rate before and after the safety change, but not on the driver's utilities for speed or accidents. A consequence of this is that either all drivers should increase their accident rate or all should decrease it, in spite of variations in utilities.The fact that rational drivers may react so that accidents may increase or decrease underlines the need for taking danger compensation into account when introducing a safety change.