Under the proposal, car owners could get a voucher worth $3,500 if they traded in a vehicle getting 18 miles per gallon or less for one getting at least 22 mpg. The value of the voucher would grow to $4,500 if the mileage of the new car was 10 mpg higher than the old vehicle. The miles per gallon figures are listed on the car window's sticker.

Owners of sport utility vehicles, pickup trucks or minivans that get 18 mpg or less could receive a voucher for $3,500 if their new truck or SUV got at least 2 mpg higher than their old vehicle. The voucher would increase to $4,500 if the mileage of the new truck or SUV was at least 5 mpg higher than the older vehicle.

Dealers participating in the program would receive an electronic voucher from the government for the trade-in to apply to the purchase or lease of a qualifying vehicle. The bill directs dealers to ensure that the older vehicles are crushed or shredded to get the clunkers off the road.

The program was intended to help replace older vehicles — built in model year 1984 or later — and would not make financial sense for consumers owning an older car with a trade-in value greater than $3,500 or $4,500.