From AP.com: ALL BUSINESS: Don't count on gas tax cut lowering prices

That's because the idea proposed by presidential candidates John McCain and Hillary Clinton to ease the federal gas tax would strip the U.S. government of about $10 billion for roadway and transportation projects.

And the plan doesn't even guarantee that lower taxes will lead to lower gas prices. Just the opposite might happen if the tax holiday spurs more demand for gas at a time when supply is already constricted.

The gas tax is fixed at 18.4 cents/gallon.  We can cut this 18.4 cents and the next week the price could rise 18.4 cents and we'd be back in the same place and then we'd be short 10 billion to fix roads.  I mean gas has risen over 30 cents in the last couple of weeks

We'd all like to see cheaper gas, but a gas tax holiday doesn't solve the fundamental problems we have and is just a political ploy.  The gas tax pays to repair our crumbling infrastructure and actually employees people in the road construction industry.