So with a total spent on roads over the last years averaging in today's dollars about $100,000,000,000,000, or simply about 100 Billion dollars I wondered what the calculation would come out to if all those costs where recouped via fuel taxes.

Currently fuel taxes sit at about $.10-.35 cents a gallon.  With that in mind it averages out to about a penny per mile.  Now I'm not sure if many realize this, but a penny a mile probably doesn't cover the above costs.  On an interstate averaging a high percentage of usage (i.e. close to 30-40mph traffic packed tight, commonly considered a "traffic jam") this comes somewhat close to covering the costs.  But then one must be reminded for every mile of Interstate there are probably 10-20x as many miles that are not Interstate, that have slower and less throughput that aren't particularly covering their costs.

So let's say conservatively the gas tax creates about 20-40 Billion of revenue per year for roadways.  That's a bit shy of the total, leaving the gas tax short of meeting its goals.

So let's say conservatively the gas tax creates about 40-60 Billion of revenue per year for roadways.  That's still pretty low compared to the total, still leaving the gas tax short.

In no scenario does the gas tax cover roadway maintenance except in certain circumstances.  Even on the vast majority of the interstates gas taxes don't cover the costs.  If they where to cover the costs the taxes would have to increase from 10-35 cents per gallon to about 60-80 cents per gallon minimum.  In addition to that if new construction and maintenance where factored in for ongoing expansion of roadways that would have to increase somewhere to the tune of $1.20-2.00 per gallon.

With that in mind, mass transit looks even more valid for many people.