Obama lie

Obama says if we just inflate our tires, it would equal the amount of oil expected by new off shore drilling. We decided to check his statement, here is what we found:
1. There are 125 million cars on the road :
http://wiki.answers.com/Q/How_many_cars_are_currently_on_the_road_in_the_US
2. 3% of them have underinflated tires (3,750,000):
http://www.msnbc.msn.com/id/3072627/
3. Each car can be expected to save 50 gal per year if they inflate their tires:
http://www.thebostonchannel.com/automotive/16380866/detail.html
4. New off-shore drilling can be expected to tap 1 billion barrels of new oil:
http://articles.latimes.com/2005/apr/25/business/fi-drill25
5. There are 42 gallons per barrell:
http://wiki.answers.com/Q/How_many_gallons_in_a_barrel_of_oil
Do the math. 3% of 125 million cars is 3,750,000 cars that are underinflated at 50 gal each equals 187,500,000 gallons per year divided by 42 equals (gallons per barrell)4,464,285 barrels per year. If oil companies expect 1 billion barrels it will provide a 227 year supply.
Obama wasn't even close, is he the only meathead or are his math wiz handlers meatheads too?