WHEN THE FEDERAL government last raised the gas tax, Hillary Clinton was the first lady of the United States. Mark Zuckerberg was a nerdy nine-year-old in suburban New York. America’s interstate highway system was aging, but working just fine. Oh, how far the country has come since August of 1993, and how far its infrastructure has … not. The motor vehicle gas tax—those 18.4 cents that get tacked onto every gallon sold in the US—remains the primary funder of the road, bridge, and transit system.