<P> There are a large number of technologies that manufacturers can apply to improve fuel efficiency short of implementing hybrid or plug - in hybrid technologies . Applied aggressively, at a cost of several thousand dollars per vehicle, the Union of Concerned Scientists estimates that these technologies can almost double MPG . </P> <P> Some technologies, such as four valves per cylinder, are already widely applied in cars, but not trucks . Manufacturers dispute how effective these technologies are, their retail price, and how willing customers are to pay for these improvements . Payback on these improvements is highly dependent on fuel prices . </P> <P> Historically, automakers and some conservative groups have believed consumers do not prioritize fuel economy . In 2003, Alliance of Automobile Manufacturers spokesman Eron Shosteck asserted automakers produce more than 30 models rated at 30 mpg or more for the U.S. market, and they are poor sellers . In 2004, GM retiree Charles Amann said statistically, consumers do not pick the weak - performing vehicle when given a choice of engines . However, after a spike in gas prices, a 2006 Consumer Reports survey concluded fuel economy is the most important consideration in consumers' choice of vehicle and a 2007 Pew Charitable Trusts survey found that nine out of ten Americans favor tougher CAFE standards, including 91% of Democrats and 85% of Republicans . In 2007, the 55 mpg Toyota Prius outsold the top - selling SUV, the 17 mpg Ford Explorer . In late 2007, GM Vice Chairman Bob Lutz called hybrid gasoline - electric vehicles the "ideal solution". In 2008, GM advertised fuel economy improvements and their upcoming Chevrolet Volt Extended Range Electric Vehicle, and developed corporate branding for their fuel economy technologies, and though GM Chairman Rick Wagoner admitted not knowing which fuel efficiency technologies consumers really want, he said "we are moving fast with technologies like E ‐ 85 (ethanol), all - electric, fuel cells, and a wide range of hybrid offers". </P> <P> In 1999, automakers asserted they couldn't lobby for the repeal of CAFE standards, because consumers would learn small cars are unsafe and not buy them, or would try to sue the manufacturers . However, NHTSA's public record shows the automakers publicly express opposition to CAFE increases . </P>

What was the average miles per gallon for american cars in 1980