A study was undertaken by Institute of Transportation Studies of the University of California at Irvine to examine the safety aspects of Jersey-type median barriers and establish their costs and benefits. It was found that the frequency of nonfatal and noninjury accidents was basically unchanged after barrier installation, and that both the frequency of fatal accidents and the frequency of fatalities decreased significantly (by 36 and 43%, respectively). The frequency of injury accidents and injuries also decreased, but not as significantly as those associated with fatalities (by 13 and 11%. respectively). Also studied was the impact of Jersey barriers on crossover accidents. Results showed that head-on accidents decreased significantly, and the fatalities associated with these accidents were eliminated. Finally, the effect of median width on the frequency of accidents was examined. It was determined that for highway sections on which the median width was decreased after the installation of Jersey barriers, the frequency of nonfatal and noninjury accidents increased (9,2 and 2,4%, respectively), whereas the frequency of fatal accidents decreased by 31.3%. Although decreased median width reduced the overall effectiveness of Jersey barriers, the reduction in fatal accidents remained significant. During cost-benefit analysis. the installation cost of Jersey barriers was compared with savings in total costs of fatalities and injuries that would be prevented by the presence of the barrier. The results indicate substantial cost savings and, more important, lives saved with the installation of Jersey barriers.
Samenvatting