Civil Engineering Reference
In-Depth Information
A 2006 survey for the ITS Deployment Database, 8 of 100 metro areas reported
using reversible lanes on 98 miles of
freeways
, representing one percent coverage
[
23
]. And 16 of 106 metro areas reported using reversible lanes on only 126 miles
of
arterial streets
. Considerable mileage was found in two metro areas (Fresno CA,
and Janesville-Beloit, WI). Other applications of this strategy were found in several
freeway bridges/tunnels (e.g., Bay Bridge in San Francisco, Walt Whitman Bridge
in Philadelphia, Tappan Zee Bridge in Westchester-Rockland counties, NY, the
Long Island Expressway approach to the Queens Midtown Tunnel (NYC), and the
Gowanus Expressway Approach to the Brooklyn Battery Tunnel (NYC).
Examples of reversible lanes include:
I-5, Seattle
the JFK Expressway, Chicago
Connecticut Avenue, Washington, DC
Highland Boulevard, Los Angeles
North Sheridan Road, Chicago
16.8.3 Strength and Weaknesses
The basic strength of reversible lanes is their ability to serve both directions of
travel. In so doing, they reduce congestion by providing a better balance between
demand and capacity at a relatively little cost. A possible weakness of reversible
lanes is an increase in the number of crashes (especially if left turns are permitted).
Therefore, roadways with reversible lanes work best when left turns are banned.
16.8.4 Application Guidelines
Reversible lanes are appropriate where [
24
]:
There are pronounced imbalances in the directional traf
c volume. The ratio of
major to minor movement should be at least 2
1.
-
Peak period and peak direction
fl
ows are recurrent.
Peak hour traf
c speeds generally are at least 25 % slower than those during the
off-peak period.
Adequate provisions are made to accommodate the traf
c in the corridor.
Adequate capacity is provided at the transitions of the beginning and end points,
and parking should be prohibited during the hours that the lanes are in effect.
Reversible lanes work best when left turns are prohibited at signalized inter-
sections. They are not compatible with the provision of protected left-turn lanes,
and they do not work well on streets with median islands.
