By the time the last snowflake falls this winter, the state will have plowed more than two million miles of highway lanes, dropped 85,000 tons of salt and 50,000 cubic yards of sand, and spent between $25 to $30 million.

Last weeki?¿1?2s snowstorm alone cost the Maine Department of Transportation $1.2 million.

As the largest snowplow operation in the state – MDOT has 559 plows as compared to the perhaps more visible Maine Turnpike with 85 – the department is always under public scrutiny. It plows 4,200 miles – the real distance multiplied by the number of lanes.

A relatively new method known as anti-icing, uses much less sand – 50,000 to 60,000 cubic yards as compared to 500,000 – and 15,000 more tons of salt, than the old method of deicing, phased out in the late 1990s.

The biggest complaint the department gets is not enough sand is used, an issue raised in the now famous skidding accident last February when Gov. John Baldaccii?¿1?2s state-issued SUV went off the highway after trying to pass another vehicle on Interstate 295 in Bowdoinham. Both Baldacci and his driver and the driver of the other vehicle thankfully escaped without serious injury.

That accident was a perfect example of the dilemma highway crews face, according to Brian Burne, a highway maintenance engineer at MDOTi?¿1?2s headquarters in Augusta.

i?¿1?2At 3 a.m. the roads were bare and wet,i?¿1?2 Burne said, but in a short period of time that morning, as the governor was heading for a chamber breakfast in Portland, there was a dramatic drop in temperature. i?¿1?2All of a sudden it freezes,i?¿1?2 and the governori?¿1?2s vehicle was passing at 65 m.p.h. and went off the road, he said.

i?¿1?2People said we should have put sand out there?If you knew it was going to do that you could have put sand or salt out,i?¿1?2 but there was no warning, he said. i?¿1?2The timing had to be totally perfect.i?¿1?2 And, that morning it wasni?¿1?2t.

Freezing rain storms are the toughest to keep up with, Burne said. i?¿1?2We actually like the big storms better. People really appreciate you more.i?¿1?2

The departmenti?¿1?2s favorite? i?¿1?2Big fluffy snowstorms,i?¿1?2 he said, where the moisture content in the snow is so low i?¿1?2you just plow it awayi?¿1?2 without putting anything down.

This past storm was a mix over two days, but it did allow MDOT to use its anti-icing formula in some parts of the state.

That formula requires the temperature to be in the 20s or above to allow trucks to put a salt brine – a salt and water solution – down on the road before the storm hits to keep the road surface from freezing. Once the snow starts falling, the trucks put down their plows and also put down rock salt – again if the temperature stays warm enough.

i?¿1?2Temperature matters,i?¿1?2 Burne said, because salt only works down to a certain degree. At 30 degrees, one pound of salt will melt 47 pounds of ice. At 15, 1 pound melts 7 pounds of ice. Get to 0, and one pound melts only four pounds of ice.

About 250 pounds of rock salt – sometimes mixed with the more expensive calcium or magnesium chloride spray to lower the working temperature – is spread per lane mile from trucks that go about 25 m.p.h. A typical route for one plow driver is 10-13 miles, or 20-26 lane miles on a two-lane highway, in a loop repeated many times over, depending on the severity of the storm. Salt goes down as needed; sand is more likely used at intersections or hills, or when iti?¿1?2s too cold for salt to work. Sand is sometimes sprayed with salt water to keep it from flying off the road.

The goal under anti-icing, Burne said, is to keep the roads down to the pavement. Under the old deicing method, crews actually let the snow build up to two inches to create a snow pack and then used a lot of sand, going through a half-million cubic yards in a season. A lot of that sand – which is put down at 1,000 pounds per lane mile – ended up in drainage ditches or blown off the road. While sand is cheaper per pound than salt, deicing was an expensive method, given waste and cleanup costs.

i?¿1?2In the end iti?¿1?2s cheaper to use salt because you use less of it, and sand fills your drainage ditches and needs to be cleaned out,i?¿1?2 Burne said.

Deicing is a method still used by cities and towns, particularly on roads with a lot of ruts or frost heaves, and where the road is windy and shaded by trees.

The plow drivers, who are part of MDOTi?¿1?2s 1,300 year-round crew, have their commercial driveri?¿1?2s license and snow fighting training. Commercial drivers are required to take breaks after so many hours on the road, but plow drivers are exempt from those rules. According to their contract, however, drivers can ask for an eight-hour break after 15 hours.

MDOT has four weather stations to monitor conditions, uses radar and weather forecasting equipment. The best judge of road conditions, however, is often the guy out on the truck.

i?¿1?2Drivers use their own judgment, their experience, their eyes. They get out and scuff their feet,i?¿1?2 to see if the road is about to freeze, Burne said. The yellow paint on the center line is a good telltale. It actually starts to freeze before the road.

i?¿1?2When Ii?¿1?2m getting a complaint that person is usually saying I should have used sand. Salt you cani?¿1?2t see?and people doni?¿1?2t know how much salt were using out there,i?¿1?2 Burne said. i?¿1?2Iti?¿1?2s a Monday morning quarterback thing.i?¿1?2