Sure, switching from a gas guzzler to a highly efficient (and probably much smaller) car is best for the environment, but it’s not a realistic solution for large families or people who can’t afford it. But don’t let the fact that you can’t buy a 40 mpg car turn you off of a trade up in efficiency anyway. A couple of economists have pointed out that “using ‘miles per gallon’ as a measure of fuel efficiency leads people to undervalue the benefits of replacing the most inefficient automobiles.” Their point: if you’re driving a gas guzzler, even a small improvement in fuel efficiency can generate significant savings.
