Democrats and Republicans have both signaled interest in tackling infrastructure this Congress, but a major question mark surrounding the issue has persisted: How do we pay for it? The U.S. Chamber of Commerce is hunting for fresh answers to that question, offering cash prizes totaling $25,000 for those “who can come up with the best, most viable ideas for a long-term sustainable funding source for infrastructure.”

Some lawmakers, along with the Chamber, have suggested raising the federal gas tax, which has remained at 18.4 cents a gallon since 1993.