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

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
Cobenefits
As shown in Figure 4.3, most idle reduction technologies will reduce air pollution, at least
for older trucks, with benefits concentrated in the vicinity of truck stops and other truck
layover areas. For newer trucks, the magnitude of the emission benefits depends upon the
APU option – whether it has after-treatment, and whether it is diesel-fueled, battery, or
thermal. Electrified truck stops and diesel-fired heaters will generally reduce NOx
emissions, although APUs provide no NOx benefits for heating and only modest benefits
for cooling. Air pollution benefits also will vary depending upon the local electricity
generation mix. Electrified truck stops in regions that rely heavily on coal may see net
increases in PM emissions, although these primarily occur in rural areas, leading to low
population exposure (Gaines et al., 2009).
Figure 3.3 Emissions Benefits of Idle Reduction Technologies
Source: Gaines et al. (2009).
APU = auxiliary power unit; DPF = diesel particulate filter (required on APUs on 2007 and newer
trucks in California); DFH = diesel-fired heater; EPS = electrified parking space.
Feasibility
Although 300,000 truck parking spots are eligible for electrification, it will not be feasible
to electrify the vast majority of truck parking spots, which are often dispersed (e.g.,
highway shoulders). As a result, the most significant gains from reduced idling will need
to result from on-board technologies such as diesel fired heaters and storage cooling air
conditioning units. From a truck owner’s perspective, the primary barriers to
implementation of anti-idling technologies include initial startup cost, low fuel prices, and
information dissemination. The added weight of APUs also may pose a barrier; APUs can
weigh a few hundred pounds, and therefore would allow truckers to carry incrementally
less payload considering a given State or Federal weight limit.
A combination of regulatory reforms, price incentives, and outreach programs can help to
combat these barriers. Some price incentives and education/outreach programs already
exist; for example, the EPA’s SmartWay program offers a variety of financing programs
for the purchase or lease of idle reduction technologies approved by SmartWay or
California Air Resources Board, and the Energy Improvement and Extension Act of 2008
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