Advancements in technologies enabling greater use of electric or
alternative fuel vehicles will continue to impact gas tax
revenues. The U.S. Energy
Information Agency estimates that fuel efficiency for
all light-duty vehicles (cars and light trucks) will steadily
increase, from an average weighted MPG of just over 20 in 2010 to
over 36 in 2040. The fuel efficiency of freight trucks also is
expected to improve, although at a slower rate, from an average
weighted MPG of over 6 in 2010 to over 8 in 2040. This projection
assumes there is not a major paradigm shift in vehicle fuel
technology, such as affordable electric cars or hybrid heavy-duty
trucks. It also assumes no shift will occur in public policy or
public attitudes that encourage people to reduce their long-term
travel habits or shift to more efficient vehicles more quickly.
Given the growing concern about climate protection and fuel price
volatility, however, such changes are likely, which would lead to
a more rapid deterioration in the long-term viability of the
current fuel tax.
SCAG projections indicate that the total number of vehicle miles
traveled in the SCAG region will increase by about 16 percent by
2035. The National Surface
Transportation Infrastructure Financing Commission also
predicts an increase in VMT nationwide. The Financing Commission
evaluated a combination of short- and long-term factors,
identifying that short-term motor fuel price volatility combined
with a weak economy could have a considerable negative impact.
They indicate that despite a recent national decline in VMT,
travel growth nationally will resume a trajectory of about 1.5 to
1.8 percent per year for the foreseeable future due to factors
such as population growth, economic growth, and land use
patterns. Accordingly, the Financing Commissions’ findings and
recommendations indicate that the most viable approach to
efficiently fund investments in transportation in the medium to
long run will be a user charge system based more directly on
miles driven (and potentially on factors such as time of day,
type of road, vehicle weight, and fuel economy) rather than
indirectly on fuel consumed. Additionally, the National
Surface Transportation Policy and Revenue Study
Commission identified consistent findings and
recommendations.
SCAG supports further research, development, and demonstration of
mileage-based user fees specific to the Southern California
context. SCAG is exploring partnerships with automobile
manufacturers and technology developers, and local/regional
business leaders in the development of a strategic action plan
and initial demonstration framework.
