BACKGROUND

The AASHTO Highway Safety Manual (HSM), first edition, provides analytic tools and techniques for estimating effects of changes to the roadway environment on motor vehicle crashes, but provides almost no information about effects on pedestrian and bicyclist crash frequency. NCHRP Project 17-84, “Pedestrian and Bicycle Safety Performance Functions for the Highway Safety Manual,” is in the process of developing crash modification factors (CMFs) and safety performance functions (SPFs) for pedestrians and bicyclists in support of a future HSM, second edition (see Special Note L below). However, the safety benefits of many pedestrian and bicycle countermeasures, especially newer  treatments, will still be unknown after completion of NCHRP Project 17-84. Furthermore, established CMFs focused on vehicle-vehicle collisions do not properly account for effects on pedestrian and bicyclist crash outcomes.

OBJECTIVES

The objectives of this research are to:

(1) develop CMFs and SPFs related to pedestrian and/or bicyclist safety countermeasures; and

(2) assess pedestrian and/or bicyclist safety outcomes associated with vehicle safety countermeasures.  

Status: Work has been initiated. The interim report is expected in September 2024.