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A superstreet, also known as a restricted crossing U-turn (RCUT), J-turn, or Reduced Conflict Intersection, is a type of road intersection that is a variation of the Michigan left. In this configuration, traffic on the minor road is not permitted to proceed straight across the major road or highway. Drivers wishing to turn left or go straight must turn right onto the major road, then, a short distance away, queue (wait) into a designated U-turn (or crossover) lane in the median. When traffic clears, they complete the U-turn and then either go straight or make a right turn when they intersect the other half of the minor road.
Contents
The superstreet typically requires four traffic light-controlled intersections, and most traffic must pass through two of them, but each light has only two phases, greatly increasing average traffic flow; there is no need for numerous left-turn phases where most traffic is waiting for only a few cars to clear the intersection. Turning movements on roads with lower cross-traffic volumes may be controlled with stop or yield signs for turning traffic rather than with signals.
Practicality
Superstreets are not very common because they require substantial Right of Way to provide a median that can accommodate truck traffic. Inconvenience to traffic on the minor road is mostly a perception issue and does not represent additional delay in most cases. However, superstreets are cheaper to construct than limited access freeways with interchanges and improve the flow of traffic on the major road.
Usage
In North Carolina, five superstreet intersections were included as a part of U.S. Route 17's recent upgrades near Wilmington, North Carolina (34.21603°N 78.018969°W / 34.21603; -78.018969). There are also three superstreet intersections in Holly Springs along the NC 55 bypass.
In Texas in 2010, several intersections on US 281 were converted to superstreet in the northern San Antonio neighborhood of Stone Oak, north of Loop 1604, to relieve rush hour congestion. In northwest San Antonio in 2011, two intersections on Loop 1604, north of State Highway 151, were converted to superstreet. In Austin, a superstreet is being phased in starting February 19, 2013, at the intersection of SH 71 and Farm to Market Road 973 east of Austin-Bergstrom International Airport not far from the eastern boundary of the Austin city limits. This becomes the city of Austin's first superstreet and the second city in Texas to feature this intersection design.
Troy, Michigan has a superstreet on West Big Beaver Road at Lakeview Drive. 42.561383°N 83.181310°W / 42.561383; -83.181310
Benefits
A study showed a 20 percent overall reduction in travel time compared to similar intersections that use conventional traffic designs; intersections experience an average of 46 percent fewer reported automobile collisions – and 63 percent fewer collisions that result in personal injury.