We haven’t updated our main funding source for roads in over 20 years Because the main source of revenue for roads is the gas tax that is a per-gallon tax, it isn’t tied to inflation. It was 22 cents when gas was $1.14 a gallon and 22 cents when it was $3 a gallon. Not being tied to inflation means that its “purchasing power”—basically how much asphalt, steel, cement can be bought with each dollar has fallen. Voters would need to approve an increase in the gas tax. In 1991, Colorado’s 22 cents per gallon tax was higher than national average, today Colorado’s gas tax ranks 37th.