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

Transportation’s Role in Reducing U.S. Greenhouse Gas Emissions: Volume 2
economic costs of driving had no effect on their travel behavior over an eight-week period,
although it was found to have increased their general environmental awareness (Tertoolen
et al., 1998). Program staff have been unable to document the benefits of It All Adds Up to
Cleaner Air, in part because of the difficulty of separating the campaign’s effects from the
many other factors that affect people’s travel behavior. A public information campaign in
Atlanta in 1998, designed to raise awareness of air pollution and its health consequences
and decrease the amount of driving on ozone alert days, was found to significantly reduce
VMT on these days (Henry and Gordon, 2003), although it is not clear that such short-term
changes could be sustained into longer-term behavior changes that reduce GHG.
At least one study has examined the impact of mass marketing campaigns specifically on
commuter behavior. An evaluation of the Commuter Connections program in the
Washington, D.C. region used a regional survey to examine the impacts three public
information strategies – a mass marketing campaign, information kiosks, and a Commute
Operations Center to provide information and other tools (ridematch lists) for alternative
modes (MWCOG, 2009). The Mass Marketing campaign was estimated to result in
35 percent recall and 0.1 percent mode shift for those who recalled the message (this mode
shift compares with a 1 percent mode shift in an earlier 2004 survey). The survey further
found that only 19 percent of shifters permanently shifted modes. The result was an
estimated regional emissions reduction of 8,200 tons of CO 2 in 2008. InfoExpress kiosks in
the District of Columbia and Northern Virginia were estimated to reduce CO 2 emissions
by 6,200 tons, and the Commute Operations Center was estimated to reduce CO 2
emissions by 83,000 tons. Despite the uncertainty in survey results it probably can be
concluded that the annual regional impacts of all information strategies were on the order
of 0.1 mmt CO 2e. If this impact were extrapolated to the 50 largest metropolitan areas in
the U.S. (representing just over half the country’s population), the benefits would be
approximately 3.0 mmt CO 2e annually.
Individualized marketing shows potentially greater promise as a travel and GHG
reduction strategy. Pilot individualized marketing programs that target both work and
nonwork travel have reported VMT reductions in the U.S. of 2 to 8 percent for targeted
populations (FTA, 2006), and GHG reductions should correspond. The net effect across
the entire population will depend upon the proportion of the population that is: 1) willing
to participate in individualized marketing programs, and 2) willing and able to make
meaningful and permanent travel behavior shifts. No evidence is currently available on
these parameters. However, if individualized marketing campaigns could effect a
5 percent VMT reduction in between 5 and 10 percent of the U.S. population, the net effect
would be an 0.25 to 0.5 percent reduction in VMT or 3 to 6 mmt CO 2e in 2030. Combining
the individualized marketing and mass marketing impacts provides an overall estimate of
6 to 9 mmt CO 2e annually.
As noted, public information campaigns can be implemented in a short timeframe but
must be sustained over time in order to have a lasting impact. There impact is likely to be
greater under conditions of higher fuel prices, where travelers have more of an incentive to
change their behavior in a way that reduced fuel consumption and emissions.
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