Express Pass is an electronic payment system along the I-15 Express Lanes. The system runs from U.S. 6 in Spanish Fork to 2300 North in Salt Lake City and from Parrish Lane in Centerville to Layton Parkway. This system helps UDOT better manage traffic on I-15 by giving more solo drivers the opportunity to use the Express Lanes while ensuring that carpooling remains a benefit. As always, carpoolers, buses, C Decal vehicles and motorcycles are the first priority in the Express Lanes and may continue to use them without charge.

The electronic system charges solo drivers by using an algorithm that adjusts the price based on traffic conditions. Costs are higher when I-15 is more congested. The lanes are divided into six payment zones with overhead signs that show the price to use each zone. Readers at several locations along the Express Lanes detect in-vehicle Express Passes as they travel through the zones and drivers' accounts are charged when they exit. UDOT uses the payments to operate and maintain the system.

The University of Utah has conducted two studies evaluating the effectiveness of the carpool lanes and the Express Lanes decal system.