The Highway Trust Fund provides funding for road, bridge, and mass transit projects across the country ' and it's running out of money. Its revenue source, the federal gas tax, at 18.4 cents a gallon, has not been raised in over two decades. Congress has been kicking this can down the road for years. There are many arguments for a leaner fund, among them, the idea that scaling back the program would force government to prioritize projects and eliminate waste. But proponents of the tax say that it still plays a vital role in supporting infrastructure, and that perpetual shortfalls have led to construction delays and uncertainty. Should Congress raise the federal gas tax?