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

Transportations Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
There are a few other potential safety concerns for resistance strategies. For example,
while electronic visions systems are just entering the market in Class 8b trucks, these
systems are being deployed as a supplement to standard side mirrors, not as a
replacement, which would require changes in safety regulations (Kenworth, 2001).
Accordingly further demonstration and testing will be required to ensure these systems
provide adequate safety and performance in the absence of side mirrors. Also, as noted
above, certain measures may result in unacceptably low air flow and component cooling if
implemented together, such as trailer side skirts and undercarriage baffles.
Adopting aerodynamic retrofits or purchasing cabs with enhanced profiles may also be
reduced due to traditional buyer preferences. The “classic” cab profile shown in Figure 3.8
is still favored by many buyers, particularly owner-operators, in spite of their
demonstrably lower efficiency (NESCCAF/ICCT, 2009).
Trailer strategies are likely to be particularly difficult to implement due to ownership and
operation practices. First, long-haul tractors and trailers are commonly owned by
different entities, with carriers controlling the tractors and shippers or other third parties
controlling the trailers. For this reason coordinated implementation of full system
packages may be difficult. In addition, since there are approximately 2.5 trailers for every
tractor in the U.S., retrofitting trailers will necessarily be less cost-effective than tractor
retrofits, for similar efficiency improvements (Schubert and Kromer, 2008). As such,
fleetwide cost estimates are adjusted for the anticipated lower utilization of trailers
compared to tractors.
The primary barriers to implementation of weight reduction technologies are cost and
difficulty of retrofits. Unlike some aerodynamic improvements, weight savings must take
place at the design stage. The notable exception would be retrofits of aluminum wheels,
as discussed above. In terms of aluminum substitution materials in the truck and trailer
structures, it also is common for owners to perceive lighter weight materials as not being
as durable (U.S. EPA, 2004c).
One potential Federal policy approach to promote adoption of these strategies is to
undertake demonstration projects and information dissemination for advanced truck,
trailer, and engine designs, with coordination between large long-haul freight carriers and
vehicle OEMs. To help overcome financial barriers, low-interest loans may be provided
for smaller carriers (e.g., owner-operators) to encourage retrofitting of older trucks with
significant remaining life (such as has been done through EPA’s SmartWay financing
programs). California and Texas also have implemented financial incentives to encourage
retrofitting of older heavy-duty vehicles with improved emissions control technology – a
model that could potentially be applied to fuel-saving technologies as well. The Federal
government also may play a role in helping to coordinate design improvements between
tractor and trailer manufacturers and operators in order to obtain maximum benefits from
“system” integration. The Federal government could potentially promulgate
requirements to adopt certain technologies that have been determined to be feasible and
cost-effective. This approach has been taken to control emissions of criteria pollutants and
precursors from stationary sources of pollution regulated under the Clean Air Act.
3-71