Write Up:

Motorists want to get through work zones with as little inconvenience as possible. MoDOT tries to minimize travel impacts by shifting work to night  time hours or during times when there are fewer impacts to the traveling public. Other strategies include using technology in work zones, providing valuable information to customers and innovative uses of traffic control devices to promote efficient traffic flow. To measure the effectiveness of these strategies, MoDOT monitors the performance of work zones with the greatest potential to impact traffic each quarter. The goal is to minimize the number of times a work zone creates a traffic delay of 10 minutes or more.

MoDOT has monitored 868 work zones so far this year with 356 work zones being monitored this quarter. For 2019, there have been 546 work zone delays of at least 10 minutes compared to 207 work zones delays for the same period in 2018. The total congestion for 2019 to date is 492 hours. This quarter there were 246 work zone delays that occurred in 36 work zones and accounted for 167 hours of congestion.

This quarter, projects along I-44 between Route 270 and Grand Blvd. in St. Louis County contributed 100 hours of the congestion.  Another contributor to delay was emergency repairs to the Jefferson Barracks Bridge (I-255 EB) which contributed 15.6 hours of congestion. These projects alone contributed to a total of 116 hours of the 167 hours (70%) of congestion for this quarter. Bridge improvement projects continue to be the largest contributor of delay at 84% of the total delay. 

The target for the cumulative work zone congestion statewide has been set at 180 hours for the year (45 hours per quarter). This target translates to approximately 30 minutes of work zone congestion per day statewide.

Purpose of the Measure:

Work Zones are designed to allow the public to travel through safely and with minimal disruptions.  This measure indicates how well significant work zones perform.

Measurement and Data Collection:

Work zone impacts are identified using automated data collection or by visual observations.  An impact is defined as the additional time a work zone adds to normal travel.  Impacts resulting in a delay of at least 10 minutes are included in this report.  The targeted hours of work zone congestion are based on the previous years' data and an acceptable tolerance of 30 total minutes for work zone congestion statewide.  The target for this measure is updated quarterly.