Seat belts saved an estimated 115 lives in Massachusetts in 2016, and 45 more could have been saved if 100 percent of drivers and passengers buckled up, according to data released Wednesday. 

A new study, conducted by the University of Massachusetts Traffic Safety Research Program on behalf of the Executive Office of Public Safety and Security, found seat belt usage rose nearly 8 percent from 73.7 percent in 2017 to 81.6 percent in 2018, representing the largest year-to-year hike in state history. 

The national seat belt use rate was 90.1 percent in 2016, according to the National Highway Traffic Safety Administration. 

Under state law, all occupants of private or commercial motor vehicles must be restrained by seat belts. Massachusetts does not have primary enforcement of its seat belt law, so drivers can only be cited for violations if police pull them over for another reason. 

Lawmakers have for years filed bills to make not wearing a seat belt a primary offense, for which police could stop drivers, but concerns about privacy and the potential for overzealous enforcement or racial profiling have stymied the efforts.