The government’s Cash for Clunkers plan has dominated headlines this week – working so well in some places that dealerships have run out of cars.

Nightly Business Report’s Xchange blog details how the program is working so far, and which members of Congress are voicing their support to extend it.

“Today, Senators Diane Feinstein (D-California) and Susan Collins (R-Maine) announced their support for extending the program. Despite earlier concerns, they are happy with how consumers are using the program, particularly the increase in the number of fuel efficient vehicles purchased.”

But some senators are skeptical, Capitol News Connection reports:

Sen. Claire McCaskill (D-MO) said she worries any new spending will further burden taxpayers.

“Most of the folks who are buying cars with this program would have probably bought a car. Maybe not today or tomorrow or next week, but probably in the next 18 months,” McCaskill said. “What does that say for demand next year, when this recovery needs to be sustained? Aren’t we just robbing Peter to pay Paul?”

KCRW’s “Which Way LA” spoke with California car dealers who are hoping Cash for Clunkers funding continues.

And for a car-related (and gas-saving) fun fact of the day, NewsHour’s Paul Solman finds out why different makes of cars have the fuel doors on different sides.

Economic Naturalist author Robert Frank explains:

“Putting fuel filler doors on different sides of different cars thus means that some cars can access pumps from the left. And this makes it less likely that drivers will have to wait in line for gas. That benefit greatly outweighs the cost of occasionally pulling up to the wrong side of the pump in a rental car.”