IDOT US Route 45 J-Turn Project

The intersection of US Route 45 and Central Ave/Flatville Road has a history of high crash rates marked by serious crashes. Because of this, it is a priority intersection of the IL Department of Transportation (IDOT). IDOT believes in partnering with Illinois communities statewide to promote a safer, sustainable, and effective transportation system for Illinoisans. 

The J-Turn is an alternative to traditional roadway intersections on four-lane highways. 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. In addition, acceleration lanes are constructed to allow traffic an opportunity to gain speed after turning onto the highway.

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

The goal of these turns is to greatly reduce - or even eliminate - a significant number of severe crashes which are common when drivers must cross busy highways to reach another road.

In a traditional intersection of this type there are 42 different conflict points where an accident can occur. Twenty-four of those 42 conflict points can result in severe accidents (i.e. T-bone and right-angle accidents). J-Turn intersections have no more than 24 possible conflict points. J-Turn intersections can be designed so there are zero crossing conflict points.

• Eliminates or reduces the highest risk movements – directly crossing multiple lanes of traffic and left turns
• Shown to reduce fatalities by 70% and reduce injuries by 42% nationally
• Designed to help prevent severe broadside or "T-bone" crashes
• Simplifies navigation and traffic flow moving traffic safely and effectively
• Can be designed and built quickly to address future accidents from occurring

As part of its comprehensive review of design options for this intersection, IDOT compared the J-turn design with several other alternatives. Signalization of the intersection was one of the first options considered for this project. Typically, traffic signals are a cost effective way to improve intersection safety. However, due to the location of this intersection, crashes would likely increase on US Route 45.

* Traffic data was obtained on September 13, 2024 by George Butler Associates.