For decades, the words “public transit” and “Maine” rarely would be found in the same sentence. Other than in Portland, Lewiston-Auburn and Greater Bangor, most of Maine’ s 1.3 million residents have settled sparsely across its many towns and villages or “sprawled” in the regions between them.

Attempts at establishing public transportation systems, usually geared toward lower-income users, were not embraced by users.

But $4 per gallon gasoline — and the realization that cheap and abundant oil is fading away in the rear view mirror — changes all that.

The Conservation Law Foundation has urged New England states to ramp up spending on public transportation over the next five years to 75 percent of their budgets. That’ s not likely to happen, nor is it practical, but the thinking behind the challenge is intriguing. Not only would gasoline consumption and greenhouse gas emissions decline significantly, but the roads and bridges would last longer and need less maintenance because they would get less use.

A sensible way to approach reviving public transit would be to consider Maine’ s two dozen or so service center communities. Parking areas could be identified outside those centers along numbered secondary roads, and buses or vans could be subsidized to run to and from the hub centers and between the centers. The state Department of Transportation could offer grants for pilot programs in each of Maine’ s 16 counties to gauge the potential for further development.

Skeptics may question whether public transit would be used by Mainers who — like most Americans — are in love with their vehicles and the freedom they represent. There are sound reasons to believe public transit would be used. The Island Explorer and other versions of the bus system that are being developed in other parts of the state have been successful with ridership exceeding projections. The same is true of Amtrak’ s Downeaster passenger train. Midcoast communities like Brunswick and Rockland are clamoring for links to this rail service south.

The Environmental Defense Fund reports that Americans drove 9.6 billion fewer miles this May compared to May 2007. The group also reports that Americans took 10.3 billion trips on public transportation during 2007, the highest number in 50 years. This year’ s total is bound to be significantly higher.

Interestingly, traveling without a car between places like Bangor, Ellsworth, Machias, Belfast, Rockland and Augusta was actually easier in the early- and mid-20th century. There was regular passenger train service between those communities, and coastal steamboats linked waterfront communities with each other and with Boston. The Interstate highway system put an end to passenger rail in Maine.

While no one would advocate closing I-95, targeted investment in public transit should be on Maine’ s transportation agenda.