Write Up:

Motorists want to travel through work zones with as little inconvenience as possible. MoDOT tries to minimize travel impacts by shifting work to nighttime 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 489 work zones this year. For 2020, there have been 178 work zone delays of at least 10 minutes compared to 300 work zones delays for the same period in 2019. The total congestion for 2020 is 137.6 hours. Delay and congestion for the first quarter of 2020 were slightly down from the first quarter of 2019.  In the second quarter of each year, delays were reduced from 201 to 80.  Hours of congestion were reduced from 210.8 to 50.3.

This year, work on the Blanchette Bridge in St. Louis contributed to 45.7 hours of congestion, while the bridge rehab at the I-270/44 Interchange added 34.3 hours.  The Missouri Highway 25 overlay in Stoddard County added 19 hours and the pavement repairs on I-70 eastbound in St. Charles County added 10.2 hours. To date, these projects have contributed a total of 109.2 hours of the 137.6 hours (79%) of congestion. Overall, bridge improvement projects continue to be the largest contributor of delay at 70% . 

The target for the cumulative work zone congestion statewide is 180 hours per year.  This target translates to approximately 30 minutes of congestion per day statewide.

Purpose of the Measure:

Work zones are designed to allow the public to travel through them safely and with minimal disruptions.  This measure tracks the performance of significant work zones.

Measurement and Data Collection:

Work zone impacts are identified using automated data collection and 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 previous years' data and an acceptable tolerance of 30 total minutes for work zone congestion statewide.  The target for this measure is updated quarterly.