Transportation's Role in Reducing U.S. Greenhouse Gas Emissions ...

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
account, cost-effectiveness is estimated to range from -$40 to -$80 per tonne (Cambridge
Systematics, 2009). Since there was no net benefit from bottleneck relief over the 2010-
2050 period once induced demand was included, cost per tonne could not be calculated in
this scenario.
Cobenefits
Bottleneck relief will have strong cobenefits in terms of reduced delay (time savings) for
passenger and freight travelers and reduced vehicle operating costs. These time and cost
savings for travel are then passed along as benefits to the larger economy. Low-cost
bottleneck treatments have proven to be highly cost effective, even when travel time
savings is the only criterion used. For example, three low-cost bottleneck projects in the
Minneapolis–St. Paul area (ranging from $2.6 to $10.5 million) produced delay reductions
of 87,000 to over 1 million hours annually, resulting in a benefit/cost ratio of between 3:1
and 13:1 (FHWA, 2007b). This study did not consider induced demand effects.
With the exception of oxides of nitrogen (NOx), other major categories of automobile
emissions will be reduced with the reduction in congestion. Also, because crash history is
generally addressed when major interchanges are redesigned, there will be safety benefits
as well. All of these benefits accrue over multiple years after improvements are made.
The American Highway Users Alliance estimated the total benefits in several categories
from improving the top 223 bottlenecks in the country (Table 4.3). These benefits are
assumed to accumulate over the course of 20 years after improvements are made, and are
for all vehicles moving through the bottlenecks’ areas of influence, which was assumed to
extend for five miles (two and one-half miles in each direction from the bottleneck).
Again, this study did not consider any offsetting reductions in benefits as a result of
induced demand.
Table 4.3 Total Benefits from Improving the Nation’s Worst Traffic
Bottlenecks (223 Locations)
Reduction Due to
Improvement
Percentage Change Over
Benefit Type
(Over 20 Years of Project Life) Five-Mile Segment
Carbon Monoxide (million tons) 27.1 -54%
Volatile Organic Compounds (million
tons)
2.7 -50%
Carbon Dioxide (million tons) 390 -77%
Total Delay (million hours) 48,100 -77%
Total Fuel Savings (million gallons) 40,011,800 -77%
Total Crashes 449,600 N/A
Source: AHUA, 2004.
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