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Missouri Department of Transportation

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MoDOT's Kansas City District will construct its first J-turn at the U.S. 50 and Highway 58 Intersection near Centerview in Johnson County this summer. J-turns will drastically improve traffic operations in the area, creating a safer drive, and significantly reducing the number of severe crashes.

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What are J-Turns?
The J-turn is 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. Although drivers will have to travel slightly further to get where they want to go, using J-turns can take the same or less time than trying to wait for a safe and appropriate gap to cross traffic.


The point of these turns it to greatly reduce – or even eliminate -- a significant number of severe crashes common when drivers must cross-over busy highways to reach another road.

In the J-turn design drivers turn right in the same direction of traffic, and merge safely into the left lane to prepare to make a left turn in the direction they intended to travel. This option uses an extended deceleration lane, basically adding a third lane on the highway to allow traffic making a left turn onto opposing lanes to safely pull off the mainline, out of the way of high speed traffic. In addition, acceleration lanes are constructed to allow traffic an opportunity to gain speed after turning onto the highway.

How do J-turns enhance safety?

J-turns have proven to be a safer alternative to a traditional roadway intersection on a four-lane highway because they essentially eliminate right-angle crashes while lessening the severity of the other types of crashes. In fact, the installation of J-turns at similar intersections throughout Missouri and the nation have shown a substantial decrease in fatal and serious injury crashes. Basically, they eliminate the need for motorists to cross the high speed lanes of traffic to get to the opposing lanes.


Studies done by the National Cooperative Highway Research Program show J-turns provide significant reduction in right-angle, “far” side crashes. 

Recent statistics about J-turns:

A recent study conducted by the University of Missouri shows that implementing the J-turn design at intersections of high-speed rural expressways and minor roads results in fewer accidents than those that are controlled by two-way stops.

Researchers assessed five different J-turn intersections in Missouri:

  • The J-turn design resulted in a 34.8 percent reduction in crash frequency for all crashes
  • A 53.7 percent reduction in crash frequency for all injury and fatal crashes.
  • Disabling injury crashes decreased by 86 percent and minor injury crashes decreased by 50 percent.
  • Since the J-turns have been in place, none of the five study sites had a single fatality accident.
  • One of the most severe crash types, the left turn, right angle crash, was completely eliminated by the J-turn.

One location is the J-turn at Highway 63 and Deer Park Road just south of Columbia. Prior to the J-turn, there was an average of about 13 crashes annually for three consecutive years. Now with this new, innovative design, only six accidents occurred in the year after it was installed, half the number of accidents experienced prior to the J-turn.

 

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Traffic using a J-turn has a dedicated left turn

lane to safely pull out of mainline traffic.

 

Click here to see the J-turn at U.S. 50 and Highway 58.

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Check out this diagram that shows conflict points

before a J-turn and after.

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Click here for a handout about J-turns

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