If you're living in the US, I'm sure you've been bombarded by all the buzz and coverage (whether negative or positive) on the Cash for Clunkers program.
they trade in a car with low fuel economy for one with high fuel
economy, was re-funded by Congress last week. While the program’s
impact on the environment and the economy is still being debated, it
did spark hundreds of thousands of purchases of new cars with much
higher fuel efficiency".
You can check out the interactive view of the graphic here.