Snowplow Preemption


Quick and efficient removal of snow from our roadways is a key to safety. Connected snowplows can request signal preemption at intersections where the vehicle is actively plowing snow. This allows the plow to keep moving through the intersection. Efficient use of snow plow operations can significantly reduce crashes along urban corridors.


UDOT’s Snowplow Preemption Project utilizes Transit Signal Priority (TSP) technology, which is an existing technology that provides Utah Transit Authority (UTA) buses that are behind schedule with priority or extra green time at traffic signals. By leveraging this technology, snowplows that are actively plowing will be able to preempt an upcoming traffic signal, meaning that the red light will turn to green to allow the plow to move through the intersection. This allows plowing operations to be more efficient, removing the snow and ice from our roadways sooner. Snowplows are equipped with on-board units that use Dedicated Short Range Communications (DSRC) technology to send and receive messages from traffic signals that are equipped with similar DSRC roadside units.

The TSP and the Snowplow Preemption Project do differ in some ways. TSP provides conditional priority to a bus that is behind schedule and extends an existing green light, whereas the Snowplow Preemption anticipates the snowplow coming and changes a red light to green to keep the plow moving at efficient speeds.

Quick Facts








Utah winter weather can make road conditions dangerous. Quick and efficient removal of snow and ice from roadways is key to safety. A study conducted by UDOT in 2018 (1) on five urban corridors in the Salt Lake valley concluded that there are up to 89 crashes each year that occur when those roads are snowy, icy or slushy. These conditions can be mitigated sooner by improving the efficiency of snowplow operations, hopefully reducing those crashes.

The Snowplow Preemption Project is designed to heighten the effectiveness of snow removal on roads, thus keeping Utahns safe by reducing crashes caused by winter weather conditions. Studies are underway to measure the benefits.


The Snowplow Preemption Project has been operational since March 2019. The program has been deployed on five corridors in the Salt Lake Valley and uses 46 snowplows equipped with DSRC technology. The following are specific routes where it is has been deployed:

  • Foothill Boulevard from 400 South to I-80. This corridor serves as the primary arterial access to the University of Utah and has 9 signalized intersections.
  • Redwood Road from 400 South to Bangerter Highway.
  • 10400 South from Bangerter Highway to I-15. This is a significant east-west arterial with 11 signalized intersections.
  • 700 East and 900 East from 400 South to 9000 South.
  • 9000 South and 9400 South from 4000 West to Redwood Road and 700 East to Wasatch Boulevard at the mouth of Little Cottonwood Canyon. This is a major east-west arterial leading to significant roadways and two ski resorts, and it has 21 signalized intersections.

This system has also been deployed in the Provo-Orem area of Utah County, along the route of the Utah Valley Express (UVX) bus. The 47 intersections along this route already had DSRC equipment installed as part of the TSP system deployed in 2018. DSRC equipment was also installed in six UDOT snow plows.

UDOT is planning to implement additional Snowplow Preemption locations in Salt Lake County, including:

  • Wasatch Boulevard from I-215 to Little Cottonwood Canyon. This is a significant route serving major recreational areas, with 8 signalized intersections.
  • 7000 South and 7200 South from Redwood Road to State Street. This east-west corridor connects to I-15, with 7 signalized intersections.
  • Mountain View Corridor from Redwood Road to 5400 South. This divided arterial provides north-south service on the west side of the Salt Lake Valley and has 12 signalized intersections (each intersection has two signals).
  • Redwood Road from 12300 South to Porter Rockwell. This is a continuation of a corridor with 7 additional signalized intersections.
  • State Street from 400 South to 10000 South. This is a significant north-south route with 52 signalized intersections.
  • 9000 South from Redwood to 700 East. This is a section of a major east-west corridor that already has Snowplow Preemption operational to the east and west of this new section.

UDOT is also planning to expand the Snowplow Preemption Project in Utah County in the near future. About 30 additional snowplows in Utah County will be outfitted with on-board DSRC technology. The new routes will include these four additional corridors:

  • U.S. 89/State Street from 2100 North in Lehi to 100 North in Provo. This is a significant north-south corridor passing through several communities, and has 56 signalized intersections. Implementation of snowplow preemption along this route will share the DSRC roadside equipment being planned for the TSP system.
  • S.R. 92/Timpanogos Highway from I-15 to North Canyon Road. This is a heavily traveled east-west corridor with 12 signalized intersections.
  • S.R. 73/Main Street from Redwood Road to State Street. This is an east-west corridor with 12 signalized intersections.
  • S.R. 85/2100 North from Redwood Road to I-15. This is an east-west divided corridor with 5 signalized intersections.

1. Safety Impacts of Snow Plow Signal Priority Status Using Dedicated Short-Range Communication – Updated”, Unpublished Memorandum, Utah Department of Transportation, April 16, 2018.