Was to get some of the older polluting gas guzzlers off the road and replace them with something with higher mileage and less pollution - in an effort to reduce our dependency on foreign oil.
NOT boost automakers sales.

It seems most of the Ford F-150s sold were to replace older F-150s with about a 2mpg increase in mileage - really a great deal~!
NOT! They should have mandated at least a 8-10mpg increase over the older vehicle to be really effective. And it's being found out that some of the sold vehicles mileage didn't even meet that low 2mpg standard. . .