Contraflow lane reversal

From Wikipedia, the free encyclopedia

This article or section deals primarily with the United States and does not represent a worldwide view of the subject. Please improve this article or discuss the issue on the talk page.

This article does not cite any references or sources. (October 2007) Please help improve this article by adding citations to reliable sources. Unverifiable material may be challenged and removed.

Contraflow lane reversal is used to refer to plans that alter the normal flow of traffic, typically on a controlled-access highway such as a freeway or motorway, to either aid in an emergency evacuation (the most common usage of the term in the United States) or, as part of routine maintenance activities, to facilitate widening or reconstruction of one of the highway's carriageways (the most common usage in the United Kingdom).

Usually, the term is used to refer to reversal of lanes which are normally only configured for travel in one direction; changing the configuration of reversible lanes such as for rush hour is not normally considered contraflow lane reversal. Several examples exist of roads which routinely implement contraflow lane reversal for peak-hour traffic relief; see the related article on reversible lanes.

Contents 1 For use in emergency evacuation 1.1 Hurricane evacuation 2 Highway reconstruction situations 2.1 2-lane arterials 2.2 Roads with four or more lanes 2.3 Freeways and motorways 3 Other contraflow situations 3.1 Sporting events 3.2 Mass transit 3.3 Cycle lanes

[edit] For use in emergency evacuation

In an emergency evacuation situation, contraflow lane reversal doubles the number of lanes available for outbound evacuation traffic. Crossover sections are used to move outgoing traffic to these lanes. All incoming traffic is blocked until the end of the program.

Contraflow lane reversal is usually done on freeways and other controlled-access roadways; however, some examples below (particularly in South Carolina) make use of divided and undivided roadways as well. Use of contraflow lane reversal is generally considered to be an emergency measure only, as the contraflow lanes (and any associated ramps at interchanges) lack proper signage, signals, and other traffic control devices needed to orderly conduct traffic in the opposite direction. Generally, a significant number of police officers, or other officials, are needed to manually direct traffic during a lane reversal (especially at interchanges, where ramp traffic in the wrong direction must intersect with other roadways operating normally).

[edit] Hurricane evacuation

Beginning in the 1990s, many states in the southeastern United States adopted hurricane evacuation routes from coastal areas using contraflow lane reversals on interstate highways. State highway departments have coordinated plans with state highway patrol agencies for traffic direction, constructed highway median cross-overs, and installed barriers and swing arms to inhibit wrong-way collisions and signage for drivers.[1]

Most evacuation plans only involve a single state; however, the states of Louisiana and Mississippi have developed coordinated plans to evacuate the New Orleans metropolitan area using Interstate 55 and Interstate 59.

Current contraflow evacuation plans exist for:

• Alabama
  • Mobile via I-65 [2]
• Florida [3]
  • Jacksonville, via I-10
  • Pensacola, via I-10 (eastbound)
  • South Florida (Miami/Fort Lauderdale), via Florida's Turnpike and Alligator Alley
  • Southwest Florida, via I-75
  • The Space Coast, via SR 528
  • Tampa Bay, via I-4
• Georgia
  • Savannah, via I-16 [4]
• Louisiana
  • Lafayette, via I-49
  • Lake Charles, via I-10 and I-210[5]
  • New Orleans Metropolitan Area, via I-10, I-12, I-55, I-59, and the Lake Pontchartrain Causeway[6][7]
• Mississippi
  • Mississippi Gulf Coast, via I-10 and I-59[8]
• New Jersey
  • Coastal New Jersey^{[citation needed]}
• North Carolina
  • Wilmington, via I-40 [9]
• South Carolina [10]
  • Beaufort, via U.S. 21
  • Charleston, via I-26
  • Georgetown County, via U.S. 17
  • The Grand Strand, via U.S. 501
  • Hilton Head Island, via U.S. 278
• Texas [11]
  • Corpus Christi, via I-37
  • Houston, via I-10, I-45, U.S. 290, and U.S. 59
• Virginia
  • The Hampton Roads area, via I-64 [12]

[edit] Highway reconstruction situations

Sometimes when roads are being worked on and traffic is rather heavy, one lane will be blocked off but the other one may be reversed.

[edit] 2-lane arterials

A construction worker direct traffic with a sign with "STOP" on one side and "SLOW" on the other. The sign flips, and the other side proceeds. Traffic signals are also sometimes used, especially when it involves bridge construction, or any situation where a lane must be closed during times when construction crews are not at work.

[edit] Roads with four or more lanes

If road construction involves completely closing one-half of the road, roads consisting of four lanes or more will usually have two-lane two-way traffic on the other half. And detours are sometimes devised for rush hour situations.

[edit] Freeways and motorways

Controlled-access highways that are undergoing reconstruction often reduce both sides to one lane. In some cases, they will shift traffic onto one half making it a temporary two-lane freeway corridor. An example of this can be found here on Google Earth on Interstate 10 in Arizona (eastbound traffic is reduced to one lane and shifted onto the westbound half of the road). Another technique used is treating the rightmost hard shoulder as a travel lane. In the case of 6-lane freeways (3 in each direction), the third lane is often kept for the busier direction or the shoulder is opened up to allow for 4 lanes of traffic, but with little or no shoulder space (emergency breakdown areas are sometimes added, however). Usually, merge ramps on freeways, expressways and uncontrolled roads with interchanges have temporary "YIELD" or "STOP" signs for these situations.

A prominent example of a freeway contraflow in progress can be found at the Woodrow Wilson Bridge in Washington, DC. While construction is in progress on a parallel twin span, the recently-completed first span accommodates both directions (three lanes each way).

[edit] Other contraflow situations

While these traffic plans may not necessarily be referred to as contraflows, they share the essential feature of using lanes normally expected to carry one direction of traffic for vehicles traveling in the opposite direction.

[edit] Sporting events

At the beginning and end of major sporting events, the center turn lanes of roads around a stadium or arena may be used to accommodate sporting event traffic. As these lanes are typically not subject to lane control, this can be considered a limited form of contraflow reversal.

[edit] Mass transit

Many contraflow bus lanes (in which a dedicated lane of an otherwise one way street is reversed for buses and other mass transit) exist in the world. Examples include Downtown Los Angeles, California; Pittsburgh, Pennsylvania; Belfast in Northern Ireland; through the Lincoln Tunnel between New Jersey and New York City; Downtown Minneapolis, Minnesota; London, England; and for the Silver Line bus in Boston, Massachusetts. From June 1990 to June 2002, a similar line existed in Montreal, along Pie-IX Boulevard; this was indefinitely suspended after two fatalities. Government buses use a bus-only contraflow lane on Macquarie St in Hobart, Tasmania.

[edit] Cycle lanes

In several cities, cycle lanes have been created that allow cycling in the opposite direction to traffic on an otherwise one-way street.