City of Minneapolis Signal Retiming

Whenever you have a signalized intersection, it is important to keep the timing of the signal up to date with the amount of traffic using the signal.  Good signal timing can have a significant positive impact on traffic flow and vehicle emissions while bad signal timing can do just the opposite while also making drivers angry.

When the City of Minneapolis decided to retime its 787 signalized intersections, Traffic Data Inc. staff assisted Nexpro Personnel Services on the data collection for this project.  Intersection turning movement counts were needed at each intersection to understand how much traffic each signal needed to get through the intersections.  Signal timing could then be determined with this information.  Minneapolis split re-timing their 787 signalized intersections into three projects split up into Downtown, South and North/Northeast Minneapolis that were led by Alliant Engineering, Kimley Horn and SEH.

TDI recorded up to 75 intersection videos per week for several weeks each of the three years of the project.  Within the three sections of Minneapolis, certain corridors and areas were recorded on the same day.  Using COUNTcams allowed TDI to deploy up to 25 cameras at different intersections in a single day which made these groupings possible.

With the long battery life of the COUNTcam, cameras were able to be deployed on Monday to record Tuesday, picked up on Wednesday and moved to another location in the city where they could record Thursday.  They were then picked up on Friday and batteries were charged on the weekends.  Additional COUNTcams were set out on Tuesdays to record Wednesdays.

Once all of the videos were collected, TDI and Nexpro shared counting duties with a mix of 24-hour, 13-hour and 2-hour AM, Noon & PM peak period turning movement counts.  These counts were conducted using PC-TAS (now COUNTpro) software which allowed the counts to be done at increased speeds.

Having the video files for each intersection allowed TDI staff to easily do spot checks on the data if there were any questions and proved valuable for the other consulting companies as well as the City of Minneapolis to be able to answer any questions they had about intersection operations.

This project certainly seemed daunting at first, but with good planning all three stages of traffic counting were able to happen smoothly and on time.