Suburban mayors joined Chicago Mayor Rahm Emanuel to ask Illinois lawmakers to raise the state’s gas tax by 20 to 30 cents a gallon, a proposal that could make Illinois’ motor fuel tax the highest in the nation and ensure that per gallon taxes increase yearly with the rate of inflation.

Outgoing mayor Emanuel joined other mayors from suburban Chicago on Tuesday to push the General Assembly should pass a gas tax hike in January. He said the costs and use of roads have increased while funding to maintain them has been stagnant.

“We’re calling on the lawmakers, when they convene starting in January, to start to work on a number of issues that have not been addressed over the years, calling for an increase to the gas tax by 20 to 30 cents,” he said. “If you took the low range of the 20 to 30 cents that we’re talking about, the 20 cents would reflect just inflation.”