The McCain/Clinton gas tax holiday is such an irrsponsible election year BS plan on so many levels. People will save like $30 bucks. It will do nothing to reduce the longterm problem of importing too much expensive foreign oil. Its shameful really. A ploy that sounds good to the average uneducated American consumer to get their votes, but it will really make things worse. ...Like we need more bridges falling down in the country.
Thirty dollars is about right if you assume that the entire tax break will be passed on to the consumer (it won't).
The average American drives roughly 1300 miles a month. The average MPG range is 15-40. If you take the mid-point, that gets you a savings of $9-$11/month. Then multiply that over three months, and you get the $30 you stated.
But wait, here's the really stupid part of the tax break, it rewards those who drive gas guzzelers and those who drive more than the norm. If you drive a 12 MPG vehicle, you will save more than someone in a hybrid. If you run up mileage, you save more than those who don't. When global demand is the primary factor in the price of oil and gas (if you believe the oil companies) McCain and Clinton propose and idea that encourages more demand. Stupid.