Contraflow lane reversal
From Wikipedia, the free encyclopedia
Contraflow lane reversal is a program designed for quick emergency evacuation of an area. Incoming highway lanes to a city are changed to outbound lanes. This 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. 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.
Contraflow lane reversal is usually done to freeways and other controlled-access roadways. 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).
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[edit] For use in emergency evacuation
Read the article on Interstate highway for more information on facilitation of emergency evacuation plans for the United States.
[edit] Hurricane evacuation
[edit] Louisiana
Southeast Louisiana has an active program pioneered by Louisiana engineers and first used during evacuation for Hurricane Ivan in the summer of 2004. The program was designed to quickly evacuate the New Orleans metropolitan area and its out-lying regions. There are two populous parishes that connect with surrounding areas through the city of New Orleans. The plan uses Interstates 10, 12, and 55. The plan failed to effectively evacuate the city due to the lack of communication with the neighboring parishes and the "bottleneck effect" of the capital city of Baton Rouge. The normal commute time of two hours increased dramatically to 14 hours. Much of the problem of the "bottleneck effect" came from traffic "loading" onto the system (adding vehicles); loading points such as on ramps bottlenecked and traffic for miles behind each point became hopelessly mired.
The plan was changed for the summer of 2005 into a phased program sponsored by the Louisiana State Police. The Louisiana state contraflow program was activated at 4:00pm CDT on August 27, 2005, in advance of the approaching Hurricane Katrina. The program ended at 4:00pm CDT on August 28, 2005. One of the differences in the program was the blocking off of incoming traffic of interstates at the state boundaries, which is technically illegal under federal law[citation needed]. Despite this, many states have adopted similar programs for use in future evacuations.
[edit] Mississippi
Mississippi's contraflow plan was activated at the same time as the Louisiana activations. The Mississippi program affects Interstate 55 and Interstate 59 in southern Mississippi.[1] Contraflow along Interstate 59 continued from the Mississippi-Louisiana border, and stopped about 21 miles north near the town of Poplarville. Initial reports indicate that this activation was more smoothly executed than the 2004 execution of the contraflow plan.
[edit] Texas
Authorities in Texas activated a contraflow plan in order to evacuate Houston and other coastal cities in anticipation of the arrival of Hurricane Rita. This was done on Interstate 45 northbound to a point just over halfway to Dallas, and on Interstate 10 most of the way to San Antonio. This was the first instance of TxDOT ever using a contraflow plan.
[edit] Georgia
Georgia has a plan to reverse Interstate 16 west to near Dublin, in order to evacuate Savannah. As with other states, it fails to go the entire way to the next Interstate highway (in this case, Interstate 75 in Macon), potentially leaving traffic backed-up where there are little or no services available to evacuees.
[edit] Florida
Florida's contraflow plan is extensive. The Florida Turnpike opens up its southbound lanes from Ft. Pierce to Orlando. Coming from Tampa, Interstate 4 becomes eastbound-only heading toward Orlando. Interstate 10 becomes westbound-only from Jacksonville to the intersection with Interstate 75. Alligator Alley, Interstate 75 through the Everglades, can be opened up in either direction depending on which direction the evacuation should be. State Road 528 between Brevard County and Orlando becomes west-bound only. Interstate 95 and the section of Interstate 10 in the panhandle are not used as contraflow evacuation routes due to the fact that they run parallel to the coastal danger areas. [2]
[edit] South Carolina
In South Carolina, Interstate 26 may be used in contraflow to evacuate Charleston, heading northwest toward Columbia.
[edit] North Carolina
In North Carolina, Interstate 40 may be used in contraflow to evacuate Wilmington, heading northwest towards Interstate 95.
[edit] Alabama
In Alabama, Interstate 65 may be used in contraflow to evacuate Mobile, headed northeast toward Montgomery. This has been done for Ivan, Dennis and Katrina.
[edit] Virginia
Authorities in Virginia are in the process of retrofitting Interstate 64 for contraflow, to facilitate emergency evacuation of the Hampton Roads area northwest toward Richmond. Gates are being installed on eastbound entrances between I-295 east of Richmond to east of the Hampton Roads Bridge-Tunnel.
[edit] New Jersey
In New Jersey, Interstate 195 may be used in contraflow to evacuate part of the Jersey Shore, heading west towards the New Jersey Turnpike.
[edit] Contraflow lane reversal in movies
- In the movie Deep Impact, cars that were evacuating major cities near New York and New Jersey were jammed up even though they were going south in both sides of the freeway.
- In the movie Atomic Train, people were trying to leave Denver as a precaution to the explosion of the atomic bomb that was being hauled on a train.
- In a deleted scene from the movie Independence Day, two characters (who are trying to drive to Washington D.C.) almost crash their car when the highway is suddenly opened to contraflow lane reversal.
[edit] Other uses
[edit] Sports culture
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] 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 however 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.
[edit] Freeways and expressways
Freeways (usually 4 lanes or more) that are undergoing reconstruction 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] 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; 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 (MBTA) bus in Boston, Massachusetts.
