Safety benefits of converting HOV lanes to HOT lanes: Case study of the I-394 MnPASS

The study investigated whether the conversion of the I-394 HOV (high-occupancy-vehicle) lanes to HOT (high-occupancy-toll) lanes reduces the number of crashes on the mainline of I-394. Applying the Empirical Bayes method in the before-after data, it was found that the number of crashes was reduced by 5.3 percent. Using standard crash values recommended by Mn/DOT, it was found that the economic benefit of reduced crashes for 2006 and 2008 is about $5 million. This is substantial given that the tolls collected total about $1.2 million per year. After comparing the estimates derived from simple before-after approaches, it was found that these approaches tend to overstate the number of reduced crashes. Further, for the I-394 MnPASS, the HOV-to-HOT conversion was accompanied by designating access points. Therefore, it was unable to differentiate to what extent the safety benefits are attributable to the conversion.