Local–express lanes
Local-express lanes or collector-express lanes are a set of two same-direction one-way multi-lane roadways, usually on a freeway. The outer set, usually called local lanes or collector lanes, provide access to most or all interchanges. The inner set usually called express lanes provide for non-exiting traffic. If there are several interchanges that are close together, which is typical on urban freeways, the frequent exit and entry ramps on the freeway would have the effect of slowing down through traffic along the freeway. Separating traffic into mainline (express lane) and local (collector lane) service alleviates this problem.
Typically, as is the case with the Interstate 78 in Northern New Jersey and Highway 427 in Toronto, the express lanes are intended for traffic passing through the area and exclusively have the ramps to other freeways, while the collector lanes are designed strictly to serve interchanges within that area.
Often another main purpose of having a collector-express system is to "squeeze" two freeways into one corridor. For Highway 401 in Mississauga, the collector lanes serve primarily as the direct connectors or ramp extensions between Highway 403 and Highway 427 while the express lanes are designed for 401 "through traffic". (As usual, the collector lanes also serve the surface streets Dixie Road and Renforth Drive.) In this way, a collector-express system was used to "squeeze" Highway 403 into the existing Highway 401 corridor instead of having a separate Highway 403 alignment parallel to Highway 401.
Slip ramps or transfers usually connect the local and express lanes. If one slip ramp crosses over another, the result is known as a braid or "The Basketweave" (e.g., Highway 401, between Highway 400 and Keele Street).
The disadvantage is that a significant amount of right-of-way is required to accommodate a collector-express system, especially the collector lanes and the median barriers between the collector and express lanes. Transportation departments often design new suburban freeways with interchanges spaced far enough apart to eliminate the need for a collector-express system, and the land saved can be used for a wider median and/or extra lanes.
Highway 401 in the Greater Toronto Area, between Islington Avenue and Brock Road, has had the distinction of being the longest 12-lane collector-express system in the world since the late 1960s (approximately 66 km).
Examples are listed with major collector-express systems (that may handle over several interchanges) at the top, although smaller sizes will serve at least 2 interchanges.
US Examples
- The Dan Ryan Expressway in Chicago
- The Garden State Parkway in New Jersey (from South Amboy to Route 18)
- Interstate 78 in Northern New Jersey (between the New Jersey Turnpike and Route 24)
- Interstate 80 in Northern New Jersey (George Washington Bridge-Garden State Parkway and Interstate 280-Interstate 287)
- Interstate 96 in the Metro Detroit area
- Interstate 270 in the Montgomery County, Maryland, suburbs of Washington, D.C. (between Montrose Road and Interstate 370)
- Interstate 270 in the eastern suburbs of Columbus (Ohio) between State Route 16 & Noe-Bixby Road, and again between McCutcheon Road & Dempsey Road
- Interstate 271 in Greater Cleveland (Ohio) between Interstate 480 in North Randall and Interstate 90 in Willoughby Hills
- Palatine Road between U.S. Route 12 and Wolf Road through the north suburbs of Chicago has express lanes, local lanes and interchanges. It is not a freeway; instead it is called a "junior expressway".[1]
Ontario Examples
- Highway 401 in the Greater Toronto Area (Inspired by the Dan Ryan Expressway in Chicago)
- Highway 427 in Toronto
- Gardiner Expressway (former QEW) in Toronto
- Highway 400 just north of Highway 407 in the Greater Toronto Area
- Conestoga Parkway in the Waterloo Region near Highway 7 Victoria Street
Other Examples
See also
References
- ^ Carlson, Rich. As documented in Wikipedia:WikiProject Illinois State Routes/External correspondence#What is a Junior expressway?