Gubernatorial candidates, in the interest of state budget belt-tightening, have latched on to a publicly popular idea: increase the tax on diesel fuel (15 cents per gallon) to equal the tax on gasoline (19 cents per gallon), raising an additional $50 million for Michigan's suffering road system.

It seems logical enough: an increase targeted specifically at the heavy trucks that deliver commercial goods. And thanks to the highest load-limits in the country, those trucks also accelerate the deterioration of our already battered state roads.

Legally, any money derived from a diesel tax increase should be distributed according to the transportation funding formula to state highways, local roads and transit agencies. As it stands under the proposal pending in the Legislature, the money from the diesel increase would go straight to the state Department of Transportation (MDOT) for building new and wider roads. Bypassing the funding formula will rob local road commissions and transit providers of approximately $28 million dollars a year-money they should have to combat congestion and repair non-state roads battered by the same heavy trucks.

Ingham County, for example, should receive $335,000 annually to help repair our pothole-ridden roads. Instead, it would only receive $26,000-losing more than $300,000. Statewide, transit agencies, which will play an increasingly crucial role in relieving the congestion choking our urban areas, will miss out on $4.4 million each year.

In a time of fiscal difficulty, we should focus transportation dollars on fixing the current system and investing in transportation choices that relieve congestion without adding more pavement. Despite the state's push for new and wider roads, studies have proven we can't build our way out of congestion. MDOT's own studies predict that spending $900 million to widen I-75 in Detroit would save the average commuter a whopping 90 seconds a day. Congestion isn't simply a product of insufficient pavement or greater population; it's an issue of ever-sprawling suburbs and a lack of viable transportation alternatives.

Our current law provides an equitable distribution of funding to begin meeting these needs. Raising the diesel tax by four cents and dedicating it to the state will leave locals unable to patch the cracks and fill the potholes on their downtown streets and county roads. Parity between the diesel and gas taxes needs to be created in a way that ensures everyone receives their fair share of the increase, and that money should be used to move people rather than push pavement.