While antilock braking systems (ABS) have heen convincingly demonstrated to enhance test track braking performance, their effect on crash risk in actual driving remains less clear. This paper examines how ABS influences crash risk using mainly two published studies which used police-reported crashes. The published fmdings are augmented by including new data and additional results. AIl the work is based on seven General Motors (GM) passenger vehicles having ADS as standard equipment for 1992 models but not available for 1991 models. The ratio of crashes under an adverse condition (say, when the pavement is wet) to under a normal condition (say, when the pavement is dry) is compared for ABS and non-ADS vehicles. After correcting for such factors as model year effects not linked to ADS, the following associations between ADS and crash risk were found by averaging data from the five states Texas, Missouri, North Carolina, Pennsylvania and Indiana (the errors are one standard error):​ a (10 ± 3)% relative lower crash risk on wet roads compared to the corresponding comparison on dry roads;​ a (22 ± 11)% lower risk of a pedestrian crash compared to the risk of a non- pedestrian crash;​ a (39 ± 16)% increase in rollover crash risk compared to the risk of a non- rollover crash. Data from the same five states were used to examine two-vehicle rear-end collisions. Using the assumption that side-impact crashes estimate exposure, it was found that for wet roads ADS reduces the risk of crashing into a lead vehicle by (32 ± 8)%, but increases the risk of being struck in the rear by (30 ± 14)%. The results from this study and from aU available reported studies are summarized in tabular form.