Historical Efficiencies Affected Demand Relatively Quickly
Source: Department of Transportation, FHA, Highway Statistics 2001, Table VM-1.
SWhile the situation historically was different than now, it does provide an illustration of how quickly efficiency changes can affect demand.  This slide focuses on the period from 1978 through 1987, which covers part of the time when fleet efficiency was improving rapidly.

SThe graph illustrates that efficiency improvements can affect demand in less than 10 years.  During the early period from 1978 to 1982 shown to the left of the dotted line, vehicle miles traveled was basically flat, and gasoline consumption declined as car efficiencies improved.  Even after 1982, gasoline consumption growth was small as car efficiencies continued to improve, countering the increasing share of light-duty trucks in the fleet.
- During the entire 1978-1987 period, the total VMT (vehicle miles traveled) for light duty cars and trucks rose at 2.4%, which is about the same as it was between 1995 and 2001.
- But in the 1978-1987 period, there was virtually no growth in gasoline consumption, compared to an annual average growth rate for gasoline of 1.7% for the 1995-2001 period.

SBecause vehicles are further along the efficiency curve now, we might not see the dramatic percentage improvements in the future that occurred in the past.  During the late 1970’s and early 1980’s, the fuel efficiency of the new vehicles was between 45% and 55% of the average fleet on the road.  Still, the technology exists to improve fuel economy by over 30%.

SIf the United States targeted fuel economy improvement, we could see a dramatic reduction in gasoline demand growth. For example, assume 3 years to design efficiencies and then gradually introduce fuel economy improvements into new vehicles.  If new vehicle efficiency reached a 28% improvement in 7 years, by the end of 10 years, we could see demand growth more than cut in half.  That is, a “base case” 2% growth rate would fall to less than 1% within a decade.