Main Street & 10th Ave NW Traffic Signal Transitioning to Flash Mode

As part of the Main Street traffic signals replacement project, the City of Mandan will transition the traffic signals at the intersection of Main Street and 10th Avenue NW into flash mode beginning Monday, May 20. Flash mode means the light will blink red for the north and southbound approaches and blink yellow for the east and westbound approaches.

Per the requirements to accept federal funds for next year’s construction project, the signal must remain in flash mode for a minimum of 90 days because the traffic operations study has determined it unwarranted and therefore should be removed. First Avenue NW is currently in flash mode due to equipment failure. However, that signal has also been determined unwarranted and will remain in flash mode for the minimum 90 day period as well. No other traffic signals will be affected.

Additional Information 
The City of Mandan is between a rock and a hard place with regard to removal and replacement of traffic signals on Main Street and 10th Ave NW. As part of a federal aid project, the traffic signals must be removed. The City does not have the option to keep them at its own cost.

NDDOT traffic operations studies of the Main Street intersections of First Ave NW and 10th Ave NW found signals to be unwarranted based on factors such as vehicular and pedestrian traffic volume and turning movements. Essentially there’s not enough north-south traffic going straight through the light or turning left.

The City of Mandan will receive $1.7 million in federal funds toward the replacement of more than 30-year-old traffic signals at Sixth Ave NE, Collins Ave, Third Ave NW and Sixth Ave NW. The new signals will have updated video detection equipment and interconnection technology for better synchronization. The local share of the project is expected to be 10 percent or $170,000 paid for with funds from the 1 percent local sales tax. Since Main Street is part of the state highway system, the traffic signals would have to meet warrant requirements with or without federal funds in order to remain.

As advised by the NDDOT the city’s acceptance notice stated should any information arise during the design of the project that would allow the signals to remain, the City would want to pursue that option. The City also requested exploring signalized pedestrian crosswalks at both intersections if the traffic signals are removed. Two-way stops would be likely for the intersections where signals are removed.

The 90-day flashing period is a way for NDDOT to test traffic effects if the signals are removed. Unless the signal becomes warranted, the traffic signals at First and 10th Avenues NW will remain in flash mode until removed with the 2020 project.