A Median U-turn (MUT) is a type of intersection in which some left-turns or crossings from the mainline road or secondary crossroad are made using indirect, downstream U-turn movements. Though now rare in Indiana, intersections of this type are common in other states.
There are three basic forms of a MUT. Each is unique, but all feature U-turns after the primary intersection. They are a Restricted Crossing U-turn (RCUT), Reduced Conflict Intersection (RCI), and Boulevard Left.
Under the right traffic conditions, MUTs are proven to improve safety and reduce delay by separating and simplifying traffic movements. MUTs improve the ability of traffic to cross a multilane divided highway from a crossroad, and reduce the number of traffic signal phases, which frees up green time for more critical traffic movements through the primary intersection.
The MUT is an alternative to traditional intersections. MUTs are generally limited to locations where the main road has four or more through lanes divided by a median. They may be used in rural or urban areas under high- or low-speed conditions and may or may not include traffic signals. They may be used individually or in a series along a corridor.
All MUT-style crossings include a companion U-turn location away from the primary intersection to complete what would ordinarily be a direct left-turn or direct through movement from the crossroad.
MUT intersections are designed to fully accommodate the wide turning radius of tractor-trailer trucks and other large vehicles, such as school buses. Where road and median width is not sufficient to accommodate larger vehicles, an additional pavement area is added. Special provisions are also made for police, fire trucks, and other emergency vehicles to cross the intersection without making U-turns. MUT intersections maintain full service to pedestrians and bicyclists. The cost to retrofit a regular intersection to a MUT ranges from a few hundred thousand dollars to more than $1 million.
In May 2015, INDOT opened its first MUT intersection at U.S. 41 and State Road 114 in Newton County. Others are planned where crash history, traffic volumes, and other road conditions justify the design.
INDOT’s policy is to use alternative intersections where appropriate, including the Median U-turn, to support its ongoing commitment to improve safety and service delivery through innovation and cost-effective investments.
MUT Intersection Styles
The three different MUT-style intersections differ in how left turns or through movements are re-directed to the U-turn locations and whether crossroad traffic is controlled by traffic signals, stop signs, or yield signs.
With a RCUT, the main intersection is controlled with a signal and, in some cases, at the U-turns as well. A RCI has no traffic signal, only stop or yield signs. Otherwise, the two forms look and function similarly and both permit direct left turns from the mainline. Crossroad traffic wanting to turn left or pass through makes an indirect U-turn movement. Through movements for mainline traffic and right turns are made the same way as in a conventional intersection.
The Boulevard Left intersection differs from a RCUT or RCI in two ways: Direct left turns from the mainline are not permitted but occur beyond the primary intersection at the U-turn, and through movements from the crossroad are permitted.
Drivers approaching a Boulevard Left intersection from the crossroad make a left turn by first turning right, and then making a downstream U-turn. A variant of this intersection requires both the primary and secondary roads to travel through the primary intersection before making left turns at the downstream U-turns. In either case, all through and right-turn movements at a Boulevard Left are the same as a conventional intersection. With a Boulevard Left, traffic at the primary intersection is ordinarily controlled by a traffic signal, and U-turn locations may be controlled by yield signs, stop signs, or a signal in coordination with the main intersection.
MUT intersections significantly reduce the risk of severe crashes in certain traffic and road conditions. MUTs increase safety by reducing by half or more the number of possible conflicts and the points where two vehicle paths cross. Most important, the conflict points eliminated are those most likely to produce severe injuries, notably right-angle or T-bone crashes. Replacement of a conventional intersection with one of the MUT forms has been shown to cut the frequency of severe crashes by 50% to 70%.
MUT intersections not only improve safety but reduce intersection delay and overall travel time when operating under the right traffic and road conditions – despite the extra travel distance required for drivers passing through the intersection. For the RCUT and Boulevard Left, retrofitting a standard intersection will improve traffic capacity by 20% to 50%. This improved traffic capacity is achieved through more efficient traffic signal operation, including better phasing, timing, and progression or coordination with adjacent intersections. Stops are reduced by a third or more.
When operating under the right traffic and field conditions, advantages of the MUT intersection over a standard intersection design include:
- Significant reduction in the risk of crashes due to a decrease in potential conflict points, particularly for angle crashes that tend to be severe.
- Increased capacity, reduced delay, and fewer stops overall. In some cases, there is even shorter travel time for traffic movements re-directed through the U-turn.
- Low cost in relation to conventional intersection construction or modernization and to other non-traditional intersection designs.
- Often can be retrofitted to an existing intersection without the need for additional land.
- Relatively straightforward to expand in the future, if necessary.
- A RCI may permit an existing traffic signal to be removed, or may delay the need for future signal control.
- FHWA: Alternative Intersections: RCUT & J-Turns
- FHWA: Alternative Intersections: Boulevard Left
- FHWA: Boulevard Left Technical Brief
- J-Turn Intersection Safety
- How to Drive a J-Turn
- How a J-Turn Intersection Works
- Reduced Conflict Intersections
Director of Traffic Engineering
100 N. Senate Ave. Room N955
Indianapolis, IN 46204