MnPASS Pricing and Its Benefits to Drivers

The MnPASS system allows solo drivers to travel in carpool lanes for a fee. The system was implemented in 2005 when it was clear that carpool lanes on I-394 were underutilized. Drivers purchase a transponder that reports when they are using the carpool lane—now called the High-Occupancy Toll (HOT) lane. This article uses real data to determine the impact of that system on traffic flows and to document the benefits. The research finds this real-time pricing system is working well for both those in the HOT lane and those in general-purpose lanes. The goal of the MnPASS system is to reduce congestion, with an emphasis on keeping those in the HOT lanes moving at a minimum of 50 mph. Solo drivers with transponders can choose to travel free in the general-purpose lanes—or to pay a fee, in the form of an electronically collected toll, to travel in the HOT lane. MnDOT uses a real-time pricing system that adjusts the prices every 3 minutes based on traffic flows. Higher prices are charged when the system senses congestion in the HOT lane. Total costs can be as high as $8 for a trip from the western suburbs to downtown Minneapolis. Higher prices signal solo drivers about congestion ahead, forcing them to decide between a faster trip in the HOT lane and a no-cost but slower trip in the general-purpose lanes. The I-394 MnPASS system is shown in Figure 1. It covers the full length of road, from I-494 in the west to I-94 in the east, and provides the major access link to downtown for commuters in the western suburbs. The system consists of two segments. West of Highway 100, the HOT lane is separated from general-purpose lanes by double-painted lines and marked with diamonds. Between Highway 100 and downtown, a 3-mile-long reversible segment is situated between the eastbound and westbound lanes, separated by concrete barriers. For inbound motorists, there are four separate entrances to the diamond lanes and one entrance to the reversible lanes. Quantifying motorists’ values of time on the road is crucial to understanding the policy implications of real-time pricing. To measure motorists’ value of time on the road, a data set that reflects how motorists make entry decisions on the road was necessary. The data used contain de-identified MnPASS data from October 2009