University of California Transportation Center

A three-year experiment is underway in San Diego County, California that allows solo drivers to pay a fee to use "Express Lanes" i.e. carpool lanes to avoid an eighty-mile highly congested stretch of freeway. These lanes are also commonly referred to as High Occupancy Toll (HOT) Lanes. The facility has two reversible lanes in the freeway median separated by concrete barriers from the I-15 main lanes with access available only at the two end points. Tolls charged commonly range from $.50 to $4.00 per trip but in exceptionally congested conditions can go as high as $8. Fees charged can change dynamically every six minutes to reflect changing traffic in the carpool lanes. Changeable message signs post the price. The algorithm controlling the prices is adjusted to maintain free flow conditions in the carpool lanes at all times. Carpools of two or more persons retain free travel. Subscribers who chose to use the lanes are charged the posted toll using transponder technology and monthly credit-card billing. The opening hours for the Express Lanes are 5:45 to 9:15 a.m. inbound to San Diego and 3:00 - 7:00 p.m. outbound from San Diego.