Prioritization for heavy commercial vehicles at signalized intersections would reduce travel times of 22 percent of northbound trucks and 10 percent of southbound trucks.

Evaluation of a truck detection system at a signalized intersection in Sherburne County, Minnesota

Clear Lake, Sherburne County,Minnesota,United States

Summary Information

MnDOT tested the truck detection system at the intersection of TH 24 and Country Road 8 in Sherburne County. Candidate intersections were chosen based on the following criteria:
  • Signalized
  • Single lane approaches
  • Truck traffic consists of 10 -15 percent of overall traffic
  • Not located near another signalized intersection
  • No advanced flasher system
MnDOT choose the intersection of TH 24 and Country Road 8 after narrowing down to 9 state intersections with the above characteristics. Of the candidate intersections, this intersection had the highest flow of truck traffic (1,800 per day).


This study selected one intersection located in Sherburne Country to test the effectiveness of prioritizing commercial vehicles at select signalized intersections. MnDOT choose this intersection because of the high volume of commercial vehicle traffic. MnDOT collected data before and after deployment of the truck prioritization system. Data was collected in one-hour intervals for both morning and afternoon peak hours and two additional non-peak hours.

Data Type

MnDOT collected stop and travel time data on each approach. In addition, data was collected on the location of trucks in the queue at the start of a green interval, with particular interest when the front vehicle was a truck and therefore all queued vehicles would be delayed by the truck’s slow acceleration.

Data Collection Techniques

Data collection occurred on three different days, providing data collection on each of the 4 one-hour time samples for each case (before and after truck priority activation).

Data Limitations:

The study is not considered statistically significant. It should also be noted that the volume of traffic in the “after? scenario was greater for all time periods than in the “before? scenario.


When extrapolated to a full year of operation, truck prioritization would result in an estimated annual delay reduction of 158 truck hours and 308 non-truck vehicle hours.
  • On average, 22 percent of northbound trucks and 10 percent of southbound trucks would be expected to benefit.
  • Average travel times and delays to both trucks and non-trucks were slightly reduced.
  • The percentage of trucks and non-trucks which stop were reduced.
  • The percentages of phase times did not change significantly between non-priority and priority cases.


    MnDOT observed a significantly greater overall traffic level between the before prioritization (Wednesday) and after prioritization (Thursday), which could have skewed the results.

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Truck Priority Evaluation

Author: Short Elliott Hendrickson Inc. 3535 Vadnais Center Drive St. Paul, MN 55110-5196 651.490.2000

Published By: Minnesota Department of Transportation

Source Date: 01/26/2012



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Goal Areas


Typical Deployment Locations



traffic signals, adaptive signals, Truck prioritization

Benefit ID: 2014-00939