PORTLAND – The cars that travel on the Maine Turnpike between York and Augusta burn more oil than all of New England’s power plants combined.

Many of those cars are making near-identical rush-hour trips between the state’s principal towns and cities.

If just a small fraction of them could instead share rides in a well-designed, convenient transit service, then Maine’s economy could save tens of millions of dollars in energy and congestion costs every year.

With volatile oil prices delivering body blows to Maine’s economy, and this summer’s historic spill in the Gulf of Mexico, Mainers everywhere are working to reduce the state’s dependency on oil.

The Maine Turnpike Authority is the government agency that’s responsible for the state’s busiest and most energy-intensive roadway. So what’s their visionary plan?

They want to build a $35 million tollbooth.

Luckily, there’s a better way, and it’s right under their noses. The Zoom Turnpike Express is a commuter shuttle that makes 10 round-trips a day between Biddeford and downtown Portland during rush hours.

It receives no subsidies from state or local governments: It is almost entirely funded from fares and the efficiencies it generates in the Maine Turnpike’s operations during the congested commuting hours.

It’s similar to the efficiency programs run by utilities during periods of peak demand, when it’s more economical to pay some customers to turn off unnecessary appliances than to build expensive new power line corridors.

The Zoom saves southern Maine motorists, and the businesses that employ them, about $1.8 million every year in avoided gasoline expenditures, congestion costs, and parking subsidies, at no cost to state or local governments. In the past five years, ridership has doubled.

But with full buses and overloaded Park and Ride lots, the future growth of the Zoom will be constrained unless the MTA makes a stronger investment in growing this proven service.

New buses running on new routes to Wells, downtown Biddeford/Saco, and downtown Lewiston/Auburn could attract hundreds of new riders, and reduce congestion on the turnpike substantially — for far less than the cost of a new tollbooth.

Unfortunately, in its newly released Ten-Year Plan, the MTA barely mentions the Zoom bus.

Instead, the agency proposes to spend more than $100 million to widen a 9-mile stretch of the highway within the city limits of Portland — a city that’s desperate to improve transit services in order to reduce parking and road maintenance expenses.

On an annual basis, the combined costs of debt and additional maintenance from this 9-mile widening alone would be more than twice the price of a regionwide bus system.

The widening proposal doesn’t make any sense — unless you happen to collect your paycheck from the tolls that Mainers pay. The MTA’s management has a direct financial incentive to make Mainers drive more, no matter what the costs to our communities or our environment.

If the MTA gets its way, then Mainers everywhere will be forced to pay much larger sums on road widenings and parking garage subsidies in southern Maine. Motorists will face increased tolls. And households will be forced to send more of their money to Texas oil companies.

Alternatively, by using the Zoom’s proven financial model, better Zoom service that serves more Maine towns could be obtained at no cost to taxpayers.

In fact, because it would postpone the need for an expensive widening project in Portland, the bus service improvements would actually result in lower tolls, and more money available for road and bridge maintenance throughout the rest of the state.

The MTA is a 60-year-old bureaucracy that lacks the vision or any incentive to make the wiser choice. That’s why Maine’s next governor, and our next Legislature, need to take the lead.

Lawmakers should force the MTA to postpone its proposed widening and provide new commuter bus services to York County and Lewiston/Auburn as a better means to manage rush hour congestion.

Transit services would also shift a substantial piece of Mainers’ spending out of the gas tank and into the state’s broader economy, thus generating more wealth in households and more income tax revenue for the state’s budget shortfall.

With more accountability and clearer goals from the state’s leadership, the MTA could be an ally in the state’s efforts to spend less money on oil, instead of being yet another enabler for out-of-state fossil fuel interests.