This is an archived article that was published on sltrib.com in 2011, and information in the article may be outdated. It is provided only for personal research purposes and may not be reprinted.
Draper • To reduce traffic congestion, Utah recently introduced newfangled "Continuous Flow Intersections." Then it introduced bizarre-looking "Diverging Diamonds." Now it has a third new type: "ThrU Turn Intersections," also known elsewhere as the "Michigan U-turn."
Before rush hour on Monday, the first new "ThrU Turn" will open at the intersection of 12300 South and State Street in Draper. Another is slated for next summer at 5400 South and 4000 West in Kearns.
"The basic concept is to take the left turn out of the main intersection" to save time now spent on left-turn signals, said Tim Rose, Region Two director for the Utah Department of Transportation.
Instead of a normal left turn, "Left turners will have to travel straight through the main intersection to a new traffic signal about 500 feet beyond it, make a U-turn [into a new, special far-right lane] and come back to the main intersection, then make a right turn to get to their destination," Rose said.
Actually, Rose said many people have told UDOT they have essentially been doing the same thing illegally and without the help of traffic lights and special lanes to get through congested intersections. Now it will be legal and safer.
"At this intersection [of 12300 South and State Street], we have 54,000 cars per day. Because of that, we had delays of up to two minutes" to get through it, Rose said. UDOT studies predicted that delays in the fast-growing area would grow to seven minutes by 2030 unless changes were made.
"When we open this thing up Monday morning, that two-minute delay will be reduced to around 25 seconds," he said.
UDOT has an animation online showing how the intersection works at udot.utah.gov/thruturn.
Rose said the design started in Michigan and is also used widely in Texas and other states and internationally in Canada and Australia.
He said not only should it make going through main intersections faster, "It will also be safer. Most accidents at intersections involve people making left turns." The new intersection cost about $5 million.
Rose said the design works particularly well at 12300 South because the U-turn signals generally are where turning lanes already existed to enter shopping centers and those lights often will help not only U-turners but people wanting to enter shopping areas.
Rose said the same idea will be used temporarily next spring at 7800 South and Bangerter Highway as a new bridge is built there, and permanently at 5400 South and 4000 West in Kearns.
Rose said the new design makes sense, and says drivers should get used to it quickly. "We don't anticipate any problems at all," Rose said.
Closure on Bangerter Highway this weekend
Bangerter Highway is scheduled to be closed in both directions from 5400 South to 6200 South this weekend until Monday at 5 a.m. Crews will be repaving the highway. East-west traffic through the intersections at 5400 South and 6200 South will remain open.