U.S. Department of Transportation
Federal Highway Administration
1200 New Jersey Avenue, SE
Washington, DC 20590
Motorists, pedestrians, and bicyclists face greater mobility challenges and safety risks at intersections as traffic volumes grow and congestion worsens. Agencies need safer, more balanced designs that keep people moving. Innovative intersection designs represent a solution, and are being built more often because they can deliver more for less.
|An RCUT is sometimes referred to as a J-Turn or a Superstreet|
The Restricted Crossing U-Turn (RCUT) is an innovative intersection design that improves safety and operations by changing how minor road traffic crosses or turns left at a major road. The RCUT does not change any of the movements that are possible from the major road.
At an RCUT, drivers stopped at the minor road waiting to cross or turn left no longer must navigate a complex intersection of two directions of traffic often traveling at high speed.
Instead, all minor road traffic makes a right turn followed by a U-turn at a designated location – either signalized or unsignalized – to continue in the desired direction, as shown in Figure 1. The RCUT is suitable for a wide variety of locations and circumstances, including, but not limited to:
Figure 1: Frederick County, MD RCUT Intersection
Source: Google Earth
The Restricted Crossing U-Turn design reduces the total number and overall severity of vehicle-to-vehicle conflict points. Comparing a conventional four-leg intersection to an equivalent RCUT design, and accounting for the U-turn locations on both sides of the main intersection, the total number of conflict points is reduced from 32 to 18 – a nearly 50 percent reduction.
Furthermore, in an FHWA study of nine Maryland intersections with unsignalized RCUT treatments:
The RCUT design also improves overall roadway operations, even when considering the additional distance traffic entering from the minor road must travel. While RCUTs can cause a slight increase in travel time during periods of low traffic volumes, they have been shown to decrease delay during periods of higher volumes, reducing the time it takes to clear an intersection and resume normal travel speeds.2
Whether signalized or unsignalized, the cost of an RCUT often is comparable to an equivalent conventional design. However, compared to a full, grade-separated interchange, RCUTs are much less costly, have fewer impacts, and can be constructed in a fraction of the time.3 This makes an RCUT an attractive option as an interim design where an interchange may not be needed for many years.
Boone County, MO RCUT Intersection
Source: RCUT Video FHWA-SA-14-020
The RCUT is an effective way for an agency to balance providing local access to the major highway with the need to deliver safer, more efficient projects. Access to local businesses and commercial areas can be maintained because the U-turns accommodate all movements. When signalized, the RCUT provides great flexibility in traffic signal timing to accommodate unbalanced traffic flow that may result from commuter patterns or retail developments.
An RCUT also can support community goals for pedestrians and bicycles. Provisions for walking and biking must be considered throughout the project development process, with the needs of pedestrians and bicycles shaping the overall design of the RCUT accordingly. This includes pedestrian crossings that are accessible to all users, and when signalized, phases that accommodate both pedestrians and bicycles. The channelization used in the RCUT design can serve as effective refuge islands for pedestrian crossings and/or as bicycle queuing areas.
1 FHWA, Field Evaluation of a Restricted Crossing U-Turn Intersection, FHWA-HRT-11-067 (Washington, DC: June 2012). Available at: https://www.fhwa.dot.gov/publications/research/safety/hsis/11067/11067.pdf [ Return to note 1. ]
2 Ibid. [ Return to note 2. ]
Jeffrey Shaw, P.E.
FHWA Office of Safety
Mark Doctor, P.E.
FHWA Resource Center
U.S. Department of Transportation
Federal Highway Adminstration