Civil Engineering Reference
In-Depth Information
Chapter 18
Overview of Mitigation Strategies
that Reduce Traf
c Demand
18.1 Introduction
Managing travel demand is increasingly recognized as a means of addressing urban
traf
c congestion
—
especially in large metropolitan areas. Commonly called
“
(TDM), the strategy focuses on reducing the
demand for single occupant vehicles. Emphasis is typically placed on reducing
vehicle-miles of travel (VMT).
The travel time and travel time variability bene
transportation demand management
”
ts of new capacity (or of existing
capacity restored) cannot be
sustained
without mechanisms that preserve these
gains in future years. To sustain the life of these bene
c demand reduction
strategies are needed because when there is pent-up demand the capacity added is
soon fully utilized.
Therefore reducing automobile travel demand becomes a necessary strategy to
keep congestion at manageable levels and to maintain mobility in future years.
The major bene
ts traf
t from demand reduction strategies on roadways congested for
several hours during each peak period, is from reducing the
duration
rather than the
intensity
of congestion.
Traf
c routes, areas or
zones. They can have region-wide applications, and they can be applied during
speci
c demand reduction strategies can be aimed at speci
c time periods. They are intended to modify person travel and goods
movement behavior by encouraging a mode shift away from private vehicles or a
time shift in trip making; by diverting trips from congested locations, and/or by
reducing the need to travel.
The synergistic effects of combining strategies can further help to relief con-
gestion. Examples include (1) coordinating transit investments with land use
planning, (2) coupling bottleneck reductions with congestion pricing, and (3)
coordinating traf
c operations improvements with pricing policies.
