Helmetless motorcyclists were more likely to be at least partly at fault in crashes than those with helmets, a new MLive Media Group analysis of Michigan State Police records shows.

They also tended to be older than helmeted riders, the review found.

The findings stem from a deeper analysis of records involving more than 1,300 motorcyclists and passengers who were in crashes since Gov. Rick Snyder repealed Michigan’s mandatory helmet law.

An earlier review of those records, published last week, showed helmetless cyclists continued to suffer more serious injuries in the three months after the helmet requirement was lifted April 12.

The new analysis indicates there are other differences as well.

According to the state police data, 49.4 percent of the 265 crashes involving helmetless cyclists were due to some form of “hazardous action” on their part, typically speeding or failure to yield. That compares to 42.1 percent of helmeted riders who were at fault in 856 crashes.

Those without helmets are also more likely to be older. The median age for helmetless riders in all crashes was 41.5 years old; the oldest was 76, who suffered non-incapacitating injuries in Emmet County on June 26.

The median for those with helmets was 34; the oldest was 88, who suffered incapacitating injuries in Presque Isle County on May 19.

Terrance Jungel, executive director of the Michigan Sheriffs’ Association, said the at-fault gap is significant, but not surprising.

“The only thing they focused on when they repealed that act was the protection of the cranium," he said. "They forget there is dust and dirt and debris that is flying at the riders on a regular basis.

“They may be laying it down, and cited for no due caution or something else, but there could be an underlying reason," Jungel said.

Anne Readett, communications chief for the state Office of Highway Safety Planning, said officials are “monitoring the crash data closely,” but generally focus more on fatalities and serious injuries and ways to avert them.

“I don’t know that we’ve looked at it from that perspective,” she said.

“We really don’t look at fatalities and those things in terms of who’s at fault,” she added. “It’s something I can bring up to say, ‘Should we look at things that way?’ and see what comes up and is there something we can do about it.”

Regarding the age gap, American Motorcyclist Association spokesman Pete terHorst said older riders tend to be more cautious than younger riders – traveling slower and preferring touring bikes to sport cycles, for example.

Those precautions might also lead to a level of security where some feel justified in not wearing a helmet, terHorst said.

Still, with both the age and at-fault gaps, terHorst and Readett emphasized it’s too soon to draw conclusions.

“You would need 12 months of numbers, and even then, from year to year, you may see a variation in numbers,” said terHorst, whose organization supports helmet use but opposes mandatory laws.

A major research project under way at Oklahoma State University should provide the best insight in a generation, he said. It is due out in 2014.

Largely funded by the federal government, the $3.8 million Motorcycle Crash Causation Study is the “most comprehensive investigation” in the U.S. into causes, rider demographics and effective deterrence in more than 30 years, according to the Federal Highway Administration.

The study was approved by Congress following concerns about rising motorcycle fatalities nationally, even as all traffic-related fatalities fell.

-- Email statewide projects coordinator John Barnes at jbarnes1@mlive.com or follow him on Twitter.