Civil Engineering Reference
In-Depth Information
attracted to the improved roadway from nullifying the travel time bene
ts of bot-
tleneck removal, strategies that reduce bottleneck congestion in highly congested
roads should be coupled with strategies that control traf
c demand on these roads
(e.g., ramp metering).
The Texas Transportation Institute Urban Mobility Report [
1
] recommends a
balanced and diversi
ed approach to reduce congestion
—
one that focuses on more of
everything. The report states that
“
current investment levels have not kept up with the
problems
and that population growth will require more systems, better operations
and an increased number of travel alternatives. In addition, most urban regions have
big problems now
”
more congestion, poorer pavement and bridge conditions, and
less public transportation services than they would like to have. The report states that
there will be a different mix of solutions in metro regions, cities, neighborhoods, job
centers and shopping areas. Some areas might be more amenable to construction
solutions, while other areas might use more travel options, productivity improve-
ments, diversi
—
ed land use patterns or redevelopment solutions. In all cases, the
solutions need to work together to provide an interconnected network of services.
Various strategies to relieve recurring congestion, and where each works best,
are summarized in Table
24. 1
.
In smaller communities, congestion relief should focus on reducing the intensity,
extent and duration of congestion. However, in larger cities priority generally
should be given to reducing the duration of the congestion.
Capacity expansion strategies generally are desirable in rapidly growing
metropolitan areas to better balance roadway supply and demand. However,
sometimes the increased capacity increases travel demand. For this reason,
strategies that mitigate traf
c demand should be combined with capacity
expansion strategies.
In very large urban areas (population more than 2 million) with strong city
centers (employment more than 100,000) and rapid transit facilities, a combi-
nation of public transport improvements, managed freeway lanes, outlying park-
and-ride facilities, and CBD parking ceilings can help relieve congestion.
Effective coordination of land development and transportation investments are
essential, especially in growing urban areas where transportation networks and
land use design should facilitate the use of public transport and should be
pedestrian and bike friendly.
24.6.4 Implementation Issues
Operational strategies that get the most use of the existing system by eliminating
bottlenecks are desirable in all communities. However, they should not merely
transfer the congestion from one location to another. Operational strategies are
relatively easy to implement when they are the responsibility of one transportation
agency.
