Using Crash Costs in Safety Analysis

There are three primary reasons DOTs invest in road and highway upgrades—to promote economic development, to alleviate congestion, and to improve safety. This monograph focuses on the third of these. Funds for safety improvements are always limited, and projects must be carefully selected to maximize the net safety improvement to society. Forkenbrock, et al. (1994) proposed a methodology for estimating the safety cost savings of various road upgrades based on reasonable dollar estimates for fatalities, personal injuries, and property-damage-only crashes. This monograph suggests current and well-accepted parameter values for preventing each of these types of crashes. We analyzed both the values of key parameters states currently use in assessing safety improvements and how they are incorporated into the investment decision-making process. We conclude with several recommendations, in particular: assigning updated dollar cost values to the three types of crashes, discounting the future benefits of avoided crashes, and discounting any future costs to their present values.