PORTLAND — Maine ended the year with 32 motorcycle deaths, the most since 1991, and safety officials say there’s no single factor that seems to be behind the spike.

Mild weather that extended the riding season through early December may have contributed to more cyclists being on the road, said Steve McCausland of the Maine Department of Public Safety. Ten of the deaths happened between September and December.

The four biggest factors in the 2015 deaths were excessive speed, alcohol impairment, lack of training and lack of a helmet — and sometimes a combination of all four, said John Kohler, motorcycle safety program coordinator for the Bureau of Motor Vehicles.

Twenty of the riders who died were ages 40 to 71. One teenage rider died.

In Waterville, James Bolduc, 53, of Fairfield, died of his injuries after he struck an SUV in a chain-reaction accident Aug. 28 on College Avenue in Waterville.

The accident was spurred by a driver backing a Chevy Suburban out of Cottage Street onto College Avenue, police said. Bolduc was riding a 2013 Harley-Davidson north on College Avenue and as the Suburban backed into road, the driver of a 1999 Jeep Grand Cherokee traveling north in front of Bolduc’s motorcycle slowed to try to avoid hitting the Suburban. Bolduc swerved in an attempt to avoid hitting the Jeep, but he struck the Jeep’s driver’s side and crashed, police said. Bolduc was not wearing a helmet. Middle-aged riders accounted for the most deaths in 2014, the most recent data available, according to the National Highway Traffic Safety Administration.

While the number of deaths of older riders wasn’t as dramatic as in the past, instructors remain concerned about aging riders.

Some older riders took a break from motorcycles and are getting back into the sport with larger motorcycles than they can handle, said Larry Caron, owner and instructor at Roy’s Driver & Rider Education.

“They’re hopping on motorcycles that are too heavy or too fast. And it’s too much for them, unfortunately,” he said.

Seventy-five percent of the deaths involved excessive speed, and 75 percent of the victims weren’t wearing helmets, Kohler said. About a half-dozen had no license or permit, he said.

Caron said he wishes motorcycle riders would take it slowly and take their rider training seriously. Riders should be wary of hopping onto a large, high-powered motorcycle until they gain experience, he said.

“You want to ease into this. You want to start off small and increase the size of your motorcycle as your skill gets better,” he said.

Training and safety gear won’t end all motorcycle fatalities, but it would help. “People say the training is too expensive, or the helmet is too expensive,” Kohler said. “Well, how much do coffins cost? How much is a funeral?”

All told, there were 155 highway deaths in Maine, according to preliminary figures. That’s an increase from 131 in 2014, the safest year on Maine roads since World War II, McCausland said.

The Morning Sentinel contributed to this report.

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