AUGUSTA, Maine — A 55-year-old grandmother who died two days before Christmas in Baring after crashing into another vehicle head-on with her grandson in her pickup truck was the last recorded Maine highway fatality of 2012, officials say.

The state recorded 164 traffic fatalities last year, a significant increase from 2011’s record low 136 figure but below the 10-year average, according to Lauren Stewart, director of the Maine Bureau of Highway Safety.

Traffic fatalities over the last decade averaged 176 annually, which is 100 less than 1970 — the worst year on record — when 276 people died on Maine roads.

Lynn Roderick, 55, of Princeton was driving north on U.S. Route 1 at about 2:20 p.m. on Dec. 23 with her 8-year-old grandson when she apparently attempted to pass another vehicle.

Her blue Dodge Ram pickup truck struck a vehicle driven by Steven Scott, 47, of Calais head-on, sending both vehicles careening off the road, Maine State Police Trooper Chad Lindsey said at the time of the collision.

Roderick, who was not wearing a seat belt, was ejected through the passenger’s window of her truck and pronounced dead at the scene by paramedics, the trooper said.

Her grandson was treated at Calais Regional Hospital for cuts and abrasions.

The state’s traffic fatalities in 2011 matched a benchmark set in 1959 and were “fantastically low,” Stewart said. The increase of 28 fatalities between 2011 and 2012 is significant, but “we can’t put our fingers on any one thing” that led to the rise, she said.

“I can tell you [almost] all of these crashes were preventable,” Stewart said. “Forty to 45 percent were not wearing a seat belt in these fatal crashes and illegal or unsafe speeds played a role as well. They’re definitely preventable.”

A total of 73 of the 164 highway deaths in 2012, or about 44 percent, involved speeders or those going too fast for road conditions, she said.

Increasing the speed limit to 75 mph on Interstate 95 north of Old Town had no effect on the road crash figures, Stewart said.

The 2012 highway deaths included 23 motorcycle fatalities, 14 teenagers between the ages of 16 and 19, nine pedestrians, one involving a bicycle and two involving moose, she said.

The biggest jump was in the number of fatalities involving those ages 20 to 24, which increased from 18 deaths in 2011 to 27 in 2012, Stewart said.

“It was mostly speed,” she said of those deaths. “And again, about half were not wearing seat belts.”

The number of alcohol-related fatalities for 2012 was not yet available, but for 2011, alcohol played a role in 39 of the 136 deaths, or approximately 28 percent, according to data compiled by Michelle Ward, a fatal accident system analyst with the Maine Bureau of Highway Safety.

Another big difference between 2012 and 2011 was the number of deaths to occur over the holiday season, Stewart said.

“Over the Christmas holiday, we had three people who died in motor vehicle crashes, but [in 2011] it was six,” she said. “Nobody was killed over the New Year’s holiday, and we had four [in 2011].”

Why 2012 was different from 2011 “can’t really be explained,” Stewart said.

BDN reporter Judy Harrison contributed to this story.