Every year, as spring arrives in Maine, the vigilance of the State Department of Transportation's (DOT) winter highway patrol is appreciated yet again. In a part of the country where winter weather conditions change suddenly and radically, many motorists and truck drivers need all the help they can get to surmount unexpected emergencies.
In many states, this kind of help often comes from state police or highway patrol officers. But in Maine, it comes largely from the DOT's highway patrol, which is not a law enforcement agency.
The DOT's reputation for rescue is impressive by any measure.
A truck carrying a load of grain along Interstate 95 on a winter night a few years ago skidded through a guard rail, plummeted down an embankment, and came to rest with its driver pinned behind his steering wheel. Grain began to pour into the cab, threatening to suffocate the trucker.
But a DOT highway patrolman out checking the highways spotted the gap in the guard rail through which the truck had crashed. He turned around, drove back, found the helpless driver, and saved his life.
Not long ago in Benton, Maine, a little town northwest of Waterville, fire broke out in a house at night. The occupants were asleep - until a DOT patrolman drove by, saw the blaze, woke the sleepers, and got them out safely. The house was destroyed.
A patrolman in Washington County came upon a woman driver stranded because of a broken fan belt. He improvised a belt from a nylon stocking, and she was able to drive into a nearby town.
And in York some time ago, an expectant mother and her husband were snowbound. A night patrolman came by and radioed for a plow. It dug the couple out, and they made it to a hospital in time.
Beginning each November and continuing through mid-April, 30 DOT patrolmen prowl the highways from 9:30 p.m. to 6 a.m., out of seven division headquarters reaching from Scarborough to Presque Isle, whenever bad storms are imminent or traveling conditions are poor.
They drive pickup trucks carrying sand and equipped with flashlights, axes, shovels, tow chains, blankets, torches, first-aid kits, and cans of gasoline.
The patrolmen radio hourly weather and road condition reports, sand dangerous icy patches, and call out plowing and sanding crews. They cover 2,400 of the 3, 400 miles the state plows - including 240 miles of Interstate highway. Night patrolmen are warned against helping drivers who appear to be drunk. They're told to report drunken drivers to their radio operators, who will call police. Requests for towing service are also turned down.
When the weather is good, the patrolmen station themselves among the 120 maintenance lots around the state and keep in touch with their night radio operators. If not called out, they repair highway equipment and guard against vandalism and theft - a serious problem in remote areas.
''The night patrols are our early-warning system,'' he says.
From mid-November of last year to early February of this year some 90 chilled , stranded motorists have been aided by alert night highway patrols. In 1982, the patrolmen helped 295 beleaguered motorists and in 1981, 225.
The Maine patrol system is in its 30th year, and Richard Scofield, the state highway maintenance engineer, who keeps in touch with transportation departments in other states, says he hasn't heard of another like it.
Patrols, Mr. Scofield says, often come upon motorists who have abandoned their broken-down cars and hiked off looking for help.
''That's the worst thing a driver should do,'' he says. ''He should put his hood up, tie a handkerchief on the radio antenna, and stay in the car until help comes.''
Night patrolmen are often first on the scene of an accident and have given first aid. They have called out sand trucks to help firemen move their equipment over icy roads to burning houses.
Scofield, a native of Waldoboro and a civil-engineering graduate of the University of Maine, has been watching winter storms since he joined the DOT 26 years ago. He has little patience with motorists who set out in winter with bald tires and worn windshield wipers, but he feels most strongly about those who fail to shift their mental gears to adjust for winter conditions.
''We have the problem of bridges freezing, and it often happens before a storm,'' he says. ''But no matter how much warning you give to drivers, they still go 55 miles an hour over the bridges.''
Wet snow, he says, is the worst, because it sticks to pavement and freezes. And when the temperature drops below 20 degrees F., as it often does in Maine, sand won't stick to ice, and roads can remain treacherous.
Backing up the night patrols' rescue work is Maine's American Automobile Association in Portland, whose telephone recording machines - available to individuals and radio stations - carry road-condition reports updated six times daily, seven days a week, or hourly during storms.
Association public-affairs director Eric Baxter advises: Keep an old blanket or a sleeping bag in the car in winter.
''Nobody plans in advance that he should have warm clothing in case he goes off the road and gets stranded,'' he says. ''So, it's good to have them in your car.''
Mr. Baxter also advises carrying dry gas, a spare fan belt, jumper cables, warning flares, ether to fight vapor lock, and a 15- or 20-pound bag of cat litter (which is more abrasive than sand and won't freeze, he says).
''Basically, what we tell our members is, 'If the road conditions are such that they endanger you, don't travel.' If it's icy or there's a blizzard, don't travel.''