Design Matters: A FOCUS on Traffic Flow
Utah ThrU-Turn Improves Safety and Wait Times
No one enjoys sitting at a red light. Especially when you’re late for a meeting or running errands in a busy commercial corridor. That’s why the Utah Department of Transportation (UDOT) continually investigates improvements and upgrades to reduce traffic and travel time and improve safety.
The field of transportation is in constant flux and FOCUS Transportation Engineering Department Manager Jason Watson makes it his responsibility to track and explore trends in transit. He regularly works with UDOT and local government agencies to evaluate data and identify effective solutions for our roadways. While he may not have designed the improvements, Jason is often asked questions about new configurations drivers encounter. He enjoys sharing the knowledge that comes from designing and managing transportation projects for two decades.
Traffic at 12300 South and Minuteman Drive
The overhaul of the intersection of 12300 South and Minuteman Drive in Draper into a ThrU-Turn is one of those improvements that Jason is frequently asked about. UDOT implemented this style of intersection for the first time in 2010 to maintain mobility and business through this key commercial artery. A UDOT study had found that during rush hours, drivers were waiting an average of 45 seconds to go through the intersection. Much of the congestion was caused by drivers turning left. While only 20 percent of the cars were making a left turn, the impacts of clogged traffic affected the other 80 percent. During peak hours, traffic often backed up a quarter of a mile to I-15.
The ThrU-Turn eliminates the need for left turn movements at the intersection regardless of the direction you’re traveling. “Instead of making a left turn, you travel straight through the intersection about 600 feet and then make a U-turn at a signalized intersection,” explains Jason. “After making the U-turn, you head back to the intersection and make a right turn to complete the left turn.”
While drivers may feel making a U-turn and then coming back to the intersection is a waste of time, the wait time at the intersection has decreased. Following the improvements, UDOT commissioned a study to evaluate the change. In addition to helping solve a safety concern, “the ThrU-Turn reduces the average delay per vehicle at the intersection from 46 seconds to an average of 16 seconds.”
A Tailored Solution: The ThrU-Turn
The ThrU-Turn is a tailored solution that considers the needs of the local community. When investigating solutions, UDOT considers how much traffic is stacking up with the left turns at an intersection. “If stacking of cars in the left turn lane exceeds the lane lengths and there are limitations to extending the lane length at an adjacent intersection, the ThrU-Turn is a good option,” Jason says. “UDOT may also look at the number and type of crashes at an intersection. If the crashes are left turning vehicles, they may consider this cost-effective way to improve safety.”
If there’s one thing Jason knows, changing transportation behaviors take time and public information is key to communicating change and teaching drivers how to move safely. Signs and lane markings are also important to guide drivers through the traffic path. He also knows that by using new technologies and better design approaches, we can better connect communities and improve quality of life.