TRAFFIC SIGNS: UDOT flips switch on electronic speed limit signs

Agency can adjust speed limit based on traffic, weather

January 08, 2014

The Utah DOT (UDOT) turned on electronic speed limit signs early January on I-80—northwest of Salt Lake City, from Parleys Canyon to near the Jeremy Ranch exit—that allow traffic engineers to adjust the speed limit. The system is designed for safety and to increase the highway’s capacity, especially during severe weather.

To determine an appropriate speed limit—which will range from 35 to 65 miles per hour—engineers look at road sensor data and traffic cameras and analyze congestion and weather conditions. UDOT then alerts the Utah Highway Patrol of the new enforceable speed limit.

The electronic signs are the first of their kind in Utah. Similar signs exist in Nevada, Wyoming, Colorado and Washington. UDOT will look to expand the $750,000 electronic sign system to other parts of the state should the current system meet expectations.