San Diego priced its I-15 HOV lanes dynamically and cut delays

San Diego's I-15 had high-occupancy lanes that ran below capacity in the peak while the free lanes jammed, so the lane's spare seats were being wasted.

In April 1999 SANDAG opened the lanes to single-occupant vehicles for a toll that rose and fell with real-time congestion, keeping the express lanes flowing while charging only those who chose to buy in.

By September 2003 about 24,700 transponders were issued, daily express-lane traffic reached 22,382 vehicles, a 143% rise from the 9,200 before pricing, with 79% still carpools and 21% paying drivers.

Sell access to spare lane capacity at a live price

A dynamic price kept the priced lanes free-flowing instead of letting them congest like the main lanes.

Carpools and buses still travelled free, so the policy did not take away existing access.

Toll revenue funded the Inland Breeze express bus, so pricing improved transit as well as driving.

Surveys found low-income users supported the pricing more than high-income ones, defusing the equity objection.

When a scarce asset has spare capacity, pricing the overflow to whoever values it most turns an idle lane into revenue and keeps it flowing.

FasTrak users saved up to 20 minutes versus main-lane travelers; tolls generated roughly $2.2 million in 2003, half of it funding the Inland Breeze express bus and the rest covering the California Highway Patrol and a customer service centre.