"Building Towards Butler County's Future"
"The Superstreet is coming! The Superstreet is coming!"
Those four words could be celebratory or a warning, depending on your understanding of Superstreet, a word with multiple meanings. In this discussion, a Superstreet is an intersection design.
Superstreet advocates believe it keeps traffic moving on major thoroughfares -- those with high traffic volumes. By reducing left turns, it is considered a safer alternative to traditional intersections with conventional traffic signal systems.
Superstreet is the plan and name used by the Ohio Department of Transportation (ODOT) as it charts future state road improvements.
In other states, different names have been given the basic concept and its variations, including J-Turn, Median U-Turn and Michigan Left Turn. Other contemporary intersection plans with similar objectives include those known as bowtie, jughandle and roundabout.
Butler County's first Superstreet intersections are likely to be on a widened and improved Ohio 4 Bypass. The Butler County Transportation Improvement District (TID) initiated the bypass upgrade in July 2002. Because it is a state highway, approval and cooperation of ODOT is required before the project can proceed. Local governments involved are the cities of Fairfield and Hamilton, Fairfield Township and Butler County.
Based on existing and projected traffic volumes, ODOT will require a Superstreet design at two intersections along the bypass -- Hamilton-Mason Road and Symmes Road.
Allowing time for preliminary studies and authorizations -- plus funding questions -- it may be a few years before motorists will drive through a Superstreet intersection on Ohio 4 Bypass.
In the Superstreet design "vehicles on the main road use conventional lanes while through traffic and left-turning traffic from side streets use median U-turns," explained Joseph E. Hummer, an engineer who has specialized in improved intersection designs and champions the Superestreet. "The design's main benefit," according to an article by Hummer, "is that it makes it easy for drivers on the main road to continue getting green lights at intersections, thus reducing stops and delays."
Hummer believes "the unconventional alternatives share two major principles. First, the emphasis is on reducing delay to through vehicles. Serving through vehicles is the main purpose of the 'arterial' functional class [road]. Second, the unconventional alternatives try to reduce the number of conflict points at intersections and separate the conflict points that remain."
Michigan began developing the Michigan Left Turn in the 1960s. That state is regarded as "the most prominent user of median U-turns in the United States, with over 1,000 miles in service." Other states using some form of Superstreet design include North Carolina and Maryland.
If ODOT requires Superstreet design at Ohio 4 Bypass and Hamilton-Mason Road, a driver westbound on Hamilton-Mason -- in order to continue west on that road -- would (1) turn right, or northbound, onto the bypass, (2) proceed to the left to the median crossover, (3) make a left U-turn onto the southbound bypass lanes and (4) then turn right at Hamilton-Mason. Through traffic on the bypass would continue without turns.
Proponents believe, even though Superstreets require some U-turns, they save motorists time because they don't have to wait while other drivers turn left or proceed straight across the intersection.
Although designed for heavy traffic areas, the scheme also improves safety in rural areas with light traffic. Rural Superstreets are aimed at reducing T-bone crashes, a deadly problem when drivers crossing a main road or turning left don't move fast enough to avoid collisions with vehicles moving at a higher rate of speed on a busier thoroughfare.
Superstreets critics cite disadvantages. They include (1) driver and pedestrian confusion when introduced; (2) some delay for cross street through traffic; (3) increased travel distances for cross street through traffic; (4) slower two-stage pedestrian crossings of the arterial road; and (5) additional right-of-way along the arterial, a factor that increases cost.
A more expensive alternate is a full interchange -- like those on the Interstate system -- which requires a highway to bridge an intersecting road, plus ramps leading to and from each road.
Because Ohio 4 Bypass work is several months away, TID and ODOT will have time to study Superstreet installations in other areas and observe problems and possible corrections.
TID, in cooperation with ODOT and the Greater Hamilton Chamber of Commerce, also plans to hold meetings and public forums to explain the Superstreet pattern. In addition, as Ohio 4 bypass planning continues, TID will issue press releases related to the project and Superstreet details.
Last Updated: November 3, 2008