Optimize Mobility

Mobility Performance Measures
Historical Mobility Index
Mobility Index


Strategic Capacity Improvements

Through a data driven prioritization process, capacity projects are selected that add new lanes or roads to the state’s roadway system. Each project is evaluated by the volume of traffic, amount of congestion, and safety. Improvements can include widening existing facilities, new interchanges on existing freeways, or additional passing lanes. Click here to view an interactive map of these projects and more information on our prioritization process.

Efficient Operations

With Utah’s population expected to double by 2040, it is important that UDOT help the traveling public make more informed decisions and work with community partners and agencies to improve access to travel choices. We seek solutions that fit community, environmental and economic needs to improve mobility through a reducing congestion on our roadways and extending the life of our assets.

Public Information

UDOT employs several tactics to inform the public of roadway construction, incidents, and other important safety information. We use variable message signs (VMS) informing drivers of expected travel times, weather conditions, and safety messages to remind travelers of our goal to reach Zero Fatalities on our roadways.

For updates and stories of how UDOT is keeping Utah moving, connect with us on social media Facebook, Twitter, Instagram, or YouTube for updates and stories. Travelers can also get up-to-date roadway information by downloading the UDOT Traffic app featuring a statewide map of current traffic conditions, traffic camera images, and road weather forecasts.

Traffic Signals

Signal Optimization

Utah is leader in the nation when it comes to signal optimization. More than 95 percent of signals in the entire state are connected to one shared system managed at UDOT’s Traffic Operations Center (TOC).This enables our engineers to develop adaptive signals to adjust cycle length times to accommodate motorist and pedestrian traffic. We are also able to reduce stops, delays, gasoline consumption and air pollution by up to 25 percent by synchronizing traffic lights.

Snow Removal

Here in Utah, we’re known for the greatest snow on earth. When winter storms occur, the public, businesses, and the economy are dependent on clear roads to safely travel to their destinations. We operate a fleet of more than 500 snow plows to remove more than 65 million tons of snow and ice on Utah’s roads every year.

UDOT also harnesses Road Weather Information Systems (RWIS), a technology that allows us assess conditions such as road temperature, wind speed, and visibility. This improves our ability to inform the public of potentially hazardous roadways conditions and strategically deploy snow plows and apply salt brines to roads.

Enable Travel Choices

Offering alternative modes of transportation will improve mobility on roadways and extend the life of our assets. By working with our community partners, we encourage and facilitate the development of an integrated transportation system that fit community, environmental, economic and transportation conditions.

The TravelWise program encourages residents to rethink the way they travel to reduce congestion on roadways. Actions such as shifting travel times to avoid primary commute periods, taking transit, or combining errands also known as trip chaining.

Enable Travel Choices Image


Mobility Performance Measures


Delay is measured as the difference between and free-flow travel time and the actual travel time. UDOT defines free-flow travel time on an arterial as the 30th percentile travel time from 7 am to 10 pm, Monday through Friday. The free-flow travel time for freeways is the time it takes to travel at 50 mph.

  • Monthly delay: Delay is calculated for all vehicles in both directions of major roads in the state for all hours every day.
Target Delay

The target delay established for January 2016 is equal to the average delay (vehicle hours of delay) experienced on a monthly basis between January 2016 and December 2016. This target delay was grown linearly by 4% to reflect historic traffic growth.


Reliability is both the measure of how consistent and how fast traffic conditions are on each roadway. There are four categories of reliability: Reliably Fast, Reliably Slow, Unreliably Fast and Unreliably Slow.

  • How Fast? UDOT measures reliability on all of Utah’s state roads, each of which have different speed limits. The Travel Time Index (TTI) is used rather than the speed limit to determine if traffic is fast or slow because the threshold needs to be dynamic. The TTI is the ratio of the rush hour travel time to the free-flow travel time. UDOT defines free-flow travel time on an arterial as the 30 th percentile travel time from 7 am to 10 pm, Monday through Friday.
  • How Consistent? The Buffer Time Index is used to determine how consistent traffic is, which we call Reliable or Unreliable. The buffer time index describes the amount of extra buffer time travelers would need to be on time 95 percent of the time.

Mode split

The graph on Mode Split below shows person trips from current volumes and UTA ridership as percentage of goal in Salt Lake County I-15 corridor during PM peak period. The normalized mode split score on the graph is determined by the dividing the percentage of transit ridership by the target of 10 percent. The maximum normalized mode split value is 100.

Snow and Ice Removal Efficiency

The pie chart on Snow and Ice Removal Efficiency shows how effectively UDOT is able to remove snow and ice from roadways around the state. This information is gathered directly from our Roadway Weather Information Systems.

Snow and Ice Removal Month to Month

The bar on Snow and Ice Removal compares snow and ice removal for the past two winter seasons. This information provides the department insight into projections and opportunities for improvement.