An innovation is coming to a particularly difficult Chicago road construction site: a Texas U-turn will be in place for drivers hoping to get on the northbound Kennedy from the eastbound Eisenhower.

Google Maps image of Meachem Road and Illinois Route 390

Kennedy-bound traffic will be detoured onto the far-right Eisenhower lane and steered to the outbound Dan Ryan Expressway. From there, motorists will take a “Texas U-turn” at the Taylor Street interchange and go from there to the westbound Kennedy…

“The detour will be a dedicated lane separated by a barrier wall to restrict merging into the regular Dan Ryan lanes and requiring drivers to use the Taylor Street interchange,” IDOT engineers said.

What’s a Texas U-turn? It “refers to a roadway that allows vehicles to make a 180-degree maneuver to go in the opposite direction, usually without traffic signals,” IDOT spokeswoman Maria Castaneda said. “They were first widely used in Texas on one-way frontage roads that paralleled expressways.

“The free flow U-turn improves traffic flow and reduces congestion in certain situations because it keeps the U-turning traffic out of the cross road intersections. An example of this is at the Meacham Road interchange on Route 390.”

According to Wikipedia, the Texas U-turn is present in a number of states.

Two additional thoughts:

1. A precondition for the Texas U-turn seems to be having frontage roads along highways. There are some areas in the Chicago region where this is common – such as long the Dan Ryan Expressway – but many other areas where frontage roads are not present and properties back up to the highway. In Chicago, I wonder if the frontage roads are the result of fitting highways into the existing street grid (such as the Congress Street Expressway, later the Eisenhower).

2. It would be interesting to see how different road innovations spread across states. How do highway innovations diffuse across the United States? They may arise because of particular local conditions but then engineers and planners elsewhere see how they are applicable. At some point, there is federal intervention regarding safety and regulations. Having driven on highways across the United States, there is both familiarity with the system – similar signage, the roadways themselves look similar – as well as local peculiarities – exits on different sides, the size of on and off-ramps as well as the space between them, HOV lanes, etc.

Related post: the coming of the diamond interchange to the Chicago area.