Where I live, we have two recently redesigned intersections, in which left hand turns have been eliminated. Called double crossover diamond interchange, it basically eliminates the need for left hand turns in front of oncoming traffic. At the North Carolina State University they have a similar proposal to reroute traffic by eliminating left turns at intersections. The new design is not meant for freeways, but instead is meant for thoroughfares where side streets intersect.
What is impressive about the super street design is that it is estimated that the design will reduce travel time by about 20%. In addition this type of traffic design will also reduce fuel usage by making traffic move more efficiently. Below is a picture of the proposed super street design:
In a recent article it also states that:
The researchers assessed travel time at superstreet intersections as the amount of time it takes a vehicle to pass through an intersection from the moment it reaches the intersection – whether traveling left, right or straight ahead. The travel-time data were collected from three superstreets located in eastern and central North Carolina, all of which have traffic signals. The superstreet collision data were collected from 13 superstreets located across North Carolina, none of which have traffic signals.
The superstreet concept has been around for over 20 years, but little research had been done to assess its effectiveness under real-world conditions. The NC State study is the largest analysis ever performed of the impact of superstreets in real traffic conditions.
The complete paper will be presented on January 24, 2011 to the Transportation Research Board Annual Meeting in Washington, D.C. , and hopefully the design will be under consideration in future designs.
In addition to smoother traffic flow, the new design will also reduce traffic collisions by an estimated 63%.
What do you think of the idea?