Want to trade in your pile of crap and get something purdy and of course, more environmentally friendly? Well, you better do it now because the U.S. Department of Transportation will end their Cash for Clunkers program on Monday.

An official from the Obama administration said that all valid transactions under the federal trade-in program must be submitted before 5 p.m. PDT Monday. The Department of Transportation is advising consumers and dealers heading into this “wind-down” period to only agree to deals in which all of the necessary paperwork has been reviewed and approved. Get more information on the Cash for Clunkers program here.

“This program has been a lifeline to the automobile industry, jump-starting a major sector of the economy and putting people back to work,” U.S. Transportation Secretary Ray LaHood said in a news release. “At the same time, we’ve been able to take old, polluting cars off the road and help consumers purchase fuel efficient vehicles.”

Washington has just added another $2-billion dollars to its incredibly popular (and probably not so eco-friendly) “cash for clunkers” program, following its initial outlay of $1-billion. The initial budget was gone within a week, even though the American government had thought it would last until November.

Buyers took quick advantage of a program offering up to $4,500 if they traded in eligible cash for clunkers cars to purchase newer, more fuel efficient models. But is this a good thing? Not according to Harvard economist Edward L. Glaser.

Glaser feels that if Americans have more fun driving newer cars, they are likely to drive more. Not to mention that they will be getting better gas mileage that will make longer drives and the daily commute much more affordable. As a result, even if they are driving more fuel efficient vehicles, “Cash for Clunkers” might not have a net GHG-lowering impact. Good for the economy yes, but for lowering carbon emissions? Not likely.