Civil Engineering Reference
In-Depth Information
Strategies that reduce automobile use in peak periods, include
transit service improvements,
fl
flexible work hours that spread the peak demand outside the peak hour,
congestion pricing,
downtown parking pricing and parking supply constraints, and
providing outlying park-and-ride facilities connected to downtown by rapid
transit lines (commuter rail, heavy, rail, light rail, BRT).
Parking pricing and road policies in city centers can relieve congestion by:
Increasing the choice of public transport for accessing the area
Increasing the availability of existing parking spaces in congested parts of the
city center at different times of the day
Reducing the incremental VMT added when searching for a parking space.
Construction of park-and-ride facilities at the periphery of the congested area
and along outer stations of rapid transit lines can relieve congestion by:
Reducing commuter VMT on radial express highways leading to the city center
Reducing parking demands and needs in city centers
Increasing transit ridership
Extending the transit market to outlying areas.
24.7.5 Metropolitan Transportation Corridors
These corridors typically consist of freeways, arterial roads, and major transit lines
connecting to centers of employment, commerce, and entertainment, as well as
serving trips passing through the metropolitan area. Travelers are subject to
recurrent congestion delays, every day, on the same roads, at the same time periods,
resulting from physical bottlenecks. The effect of this recurring delay is frequently
magni
ed by the additional delay from nonrecurring events such as incidents,
weather, special events, and road maintenance.
Congestion strategies that reduce
recurring
congestion delays at physical bot-
tlenecks involve road widening at bottleneck locations; the addition of merging and
turn lanes; and recon
guration of entrance and exit ramps at freeways and
expressways, and grade separation of con
fl
icting traf
c streams. To prevent new
traf
ts of
bottleneck removal, strategies that reduce bottleneck congestion in highly con-
gested roads could/should be coupled with strategies that control traf
c attracted to the improved roadway from nullifying the travel time bene
c demand on
these roads (e.g., ramp metering and road pricing).
However, building new freeway capacity for general use is often inhibited by
costs, environmental impacts and community opposition. Therefore, high occu-
pancy vehicle (HOV) lanes are sometimes added to heavily traveled freeway lanes,
to give travel time savings to motorists who car pool, and high occupancy toll
