Civil Engineering Reference
In-Depth Information
Commercial vehicle travel time costs (expressed in 1995 dollars) by bene
t
category and vehicle type, have been developed by the Federal Highway
Administration. Weighted hourly average costs range from about $14 for small
autos to more than $30 for 4 and 6 axle combination trucks.
Congestion cost estimates are often developed using different congestion
thresholds and different assumptions/methods. Therefore, when comparing the
results of different studies it is vital to state the assumptions used in measuring
congestion delay. The need to clarify the de
nition of congestion delay in calcu-
lating costs is essential.
The cost of traf
c congestion in US urban areas is reported annually by the
Urban Mobility Report (UMR) [
1
] and is widely quoted by the national press. The
UMR de
nes the time and fuel costs (TFC) of congestion as:
TFC
¼½
ð
actual travel time
Þð
free
flow travel time
Þ
½
value of travel time
þ
½
ð
fuel consumption in actual conditions
Þð
fuel consumption in free
flow conditions
Þ
½
unit cost of fuel
ð
24
1
Þ
:
The 2012 UMR reported an annual congestion cost of about $120 billion in
delay and fuel costs. Because these costs were calculated using free-
ow speed, as
the congestion threshold speed in
all
urban areas, the UMR report
signi
fl
cantly
overestimates
the cost of congestion.
24.6 Congestion Relief Strategies
24.6.1 General Principles
Keeping congestion from adversely affecting a community
s livability and economy
is a key societal goal. A basic objective of congestion-relief actions in large urban
areas is to reduce congestion to manageable levels since its complete elimination is
usually neither practical nor cost-effective.
Transportation enables individuals, families, and businesses to achieve social,
economic, and quality of life goals. It is a means to end (e.g., affordable housing
costs, accessibility to desired destinations, etc.). Therefore, while important at the
network level, reducing congestion should not be an end itself
'
—
rather we should
ask
”
Therefore, the perspective on how best to deal with congestion should be broadened
to include the goal of achieving vibrant, livable, and
accessible
communities.
“
to what extent is congestion limiting our ability to reach desired destinations?
