We could cut the salaries of those in government, just saying.
Check it out:

If not the gas tax, then what?

That’s the dilemma facing Congress as it seeks to plug a growing hole in transportation funding that state and local governments say is reaching crisis proportions.

While the gas tax has long been the bedrock of the transportation trust fund, the revenue is drying up as cars become more fuel-efficient and people spend less time on the roadways.

House Republicans have ruled out an increase in the tax, leaving lawmakers to search for an alternative method of funding.

But some of the ideas circulating in Washington, such as an expansion of toll roads, would likely be unpopular with the public, leaving lawmakers without an easy solution.