A University of Missouri study of five intersections in Missouri where J-turns have been installed shows the alternative solutions to traditional intersections eliminated fatal crashes and cut injury crashes in half. None of the five sites studied experienced a fatal crash after the J-turns were installed, the study reported. The evaluation period varied between one and three years depending on the site. In addition, the study found that the number of crashes resulting in disabling injuries dropped by 86 percent, while the number of all crashes at the J-turn intersections declined by 35 percent.
J-turns are an alternative to traditional roadway intersections on a four-lane highway. Instead of motorists crossing fast-moving lanes of traffic to get to the opposing lanes, drivers at a J-turn intersection turn right in the same direction of traffic, merge into the left lane, and then make a left turn in the direction they intend to travel. The main goal of J-turns is to reduce the frequency of angle accidents, which are often severe crashes. The five-site analysis showed J-turns eliminated one of the most severe crash types – the left turn, right-angle crash – while right angle crashes decreased 80 percent.
The public opinion returned in the survey was mixed. While the majority of those surveyed said the J-turns did not adversely affect their travel time, they did register some concerns. The most common complaints about the J-turns expressed in the survey were: merging difficulty after the U-turn, insufficient U-turn radius to accommodate large vehicles, general driver uncertainty and improper use of acceleration and deceleration lanes.