Reliability
About the measures
Travel time reliability measures the proportion of travel on the Interstate highway system that occurs under conditions meeting a threshold level of variation in observed travel times. The reliability of travel is an important consideration for individuals and freight. Lower percentages of reliability mean increased delays and inconsistent travel times for people and goods. The Truck Travel Time Reliability (TTTR) Index measures the consistency of commercial truck travel times on the Interstate system in a 12-month period. An index value of 1.0 is the lowest possible score and means truck travel speeds are perfectly uniform. In reality, 1.02 or 1.03 are the lowest observed index values.
Recent trends
In 2021, statewide travel time reliability on the Interstate system was 95.4% and the Twin Cities metro area was 91.2%, which were both slight decreases from 2020 but still above pre-COVID19 pandemic levels.
In 2022, the TTTR Index was 1.32, which was a slight increase from 2021 but is still below the pre-2020 values. Historically, the TTTR Index has settled between 1.4 and 1.5. By metropolitan planning organization (MPO), the Duluth-Superior MPO had the highest index with 1.6 while the Rochester and St. Cloud MPOs had lowest with 1.1.
Where we want to go
Job accessibility is a key measure to understand the multimodal transportation network in Minnesota and changes due to a variety of factors including land use, job location, transportation networks, and scheduling. Access to other key destinations such as grocery stores, hospitals, and schools can also be used to understand the multimodal network impacts. MnDOT is currently developing and implementing multimodal accessibility analysis to better understand how the transportation network impacts access to key destinations.
Increasing traffic congestion increases fuel usage and emissions, creates a higher risk for crashes, increases shipping costs, and reduces the time available to spend on other activities. Factors that affect congestion include economic conditions and population growth. To ensure reasonable travel time for commuters and travelers and reduce congestion on the interstate highway system, MnDOT currently relies on several strategies including active traffic management (e.g., an advanced system of cameras, loop detectors, and ramp meters), low-cost spot mobility improvements to improve traffic flow, E-Z Pass lanes, and strategic capacity enhancements (e.g., bus-only shoulders, unpriced dynamic shoulder lanes, and interchange capacity improvements). MnDOT also maintains and updates a Statewide Freight System and Investment Plan, a State Rail Plan, and a Statewide Ports and Waterways Plan to advance freight, railway, waterway, and multimodal planning and integration.