- Quadrant roadway intersection
A quadrant roadway intersection includes an extra roadway between two legs of the intersection. This roadway adds two three-way intersections in addition to the original four-way intersection.
The advantage is that all left-turns1 are removed from the primary intersection. Therefore, the three-way intersections may operate with three signal phases and the four-way intersection may operate with only two signal phases. The reduced quantity of signal phases improves the efficiency of the intersection.
The disadvantage, however, is that motorists wishing to turn left from either the major or minor road may have to travel further to do so. Also, right-of-way and cost limitations may reduce the feasibility of this type of intersection treatment.
1 For countries that drive on the right-hand side of the road.Grade separations
In some areas, the two main roads are grade-separated (with one traveling over the other), and the quadrant road serves to link the two main roads together. This is most frequently found in the
Greater Toronto Area inOntario ,Canada .* [http://maps.google.ca/maps?f=q&hl=en&geocode=&q=mississauga,+ontario&ie=UTF8&ll=43.59455,-79.600689&spn=0.004398,0.009978&t=h&z=17&om=1] Dundas Street and Cawthra Road, Mississauga, Ontario
* [http://maps.google.ca/maps?f=q&hl=en&geocode=&q=mississauga,+ontario&ie=UTF8&ll=43.822174,-79.477201&spn=0.008763,0.019956&t=h&z=16&om=1] Former Highway 7, Langstaff Road, and Dufferin Street, Vaughan, Ontario
* [http://maps.google.ca/maps?f=q&hl=en&geocode=&q=mississauga,+ontario&ie=UTF8&ll=43.829759,-79.453726&spn=0.008761,0.019956&t=h&z=16&om=1] Former Highway 7 and Bathurst Street, also in Vaughan, Ontario
* [http://maps.google.ca/maps?f=q&hl=en&geocode=&q=mississauga,+ontario&ie=UTF8&ll=43.836554,-79.429007&spn=0.00876,0.019956&t=h&z=16&om=1] Former Highway 7 andYonge Street ,Markham, Ontario
* [http://maps.google.ca/maps?f=q&hl=en&geocode=&q=mississauga,+ontario&ie=UTF8&ll=43.840455,-79.408128&spn=0.00876,0.019956&t=h&z=16&om=1] Former Highway 7 and Bayview Street, Markham, Ontario
* [http://maps.google.com/maps?ie=UTF8&hl=en&ll=43.875731,-78.875442&spn=0.002927,0.005021&t=h&z=18] Bloor Street and Stevenson Road, Oshawa, OntarioExternal links
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Federal Highway Administration , [http://www.tfhrc.gov/safety/pubs/04091/10.htm#1024 Alternative Intersection Treatments - Quadrant Roadway Intersection]
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