Safety Benefits of Converting HOV Lanes to HOT Lanes: Case Study of the I-394 MnPASS

Recently, the conversion of HOV lanes to HOT lanes has been increasingly popular in the United States. Several empirical studies have explored the benefits and costs associated with the conversion. However, few quantitative studies have been performed to examine the impact of HOV-to-HOT conversion on traffic safety. Introduction With the hope of relieving highway congestion and generating revenues, high-occupancy-toll (HOT) lanes have become increasingly popular in the United States. In 2005, Minnesota converted its un-derused high-occupancy-vehicle (HOV) lanes on I-394 to HOT lanes (called MnPASS). Several other HOT lanes are in full operation on the following roads: (DOT) initiated an Urban Partnership Agreement (UPA) with cities to implement complementary and synergistic strategies to relieve urban congestion. One significant strategy of UPA is tolling. For example, in Minneapolis, the HOV lanes on I-35W have been extended and converted into HOT lanes; in Miami, an HOV lane on I-95 was converted into two HOT lanes in each direction. HOT lanes provide various benefits to users and transportation agencies. 1 First, HOT lanes offer users reliable travel times by managing traffic volume through dynamic tolls, especially during peak hours. HOT lanes give solo drivers an option to pay for the privilege of high travel speed, instead of sitting in congested general purpose lanes. For example, after four HOT lanes were added to Route 91 in California, users were reported to save 12 to 13 minutes' travel time. 2,3 Second, HOT lanes may provide revenue for the construction and maintenance of HOV lanes and improving transit services. For instance, with about $1.85 million capital costs of conversion, the I-15 HOT project can generate about $1 million in revenue annually. 3 Third,