According to Michigan State Police, 138 people died in motorcycle crashes in 2015, a 23 percent increase from the number of motorcycle fatalities in 2014 and the highest number of motorcycle deaths in a year since 1985.
Researchers said the repeal of the helmet law almost certainly played a role in the increase, Michigan Radio reported.
Michigan is one of 28 states that do not require all motorcyclists to wear helmets, according to the Insurance Institute for Highway Safety.
Pettalia, who was serving his third and final state House term, was 61 years old. He was wearing a helmet when he died.