Massachusetts Could Save Lives with a Stronger Seat Belt Law, New IIHS Tool Finds
A new Insurance Institute for Highway Safety calculator shows Massachusetts could prevent about 10 deaths a year by adopting a primary enforcement seat belt law, boosting safety and compliance statewide.
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A new online calculator from the Insurance Institute for Highway Safety (IIHS) is shedding light on how Massachusetts could prevent more deaths behind the wheel by tightening its seat belt laws.
The IIHS tool, released this week, estimates that switching to a primary enforcement seat belt law—allowing police to pull drivers over specifically for not wearing a seat belt—could cut passenger vehicle crash deaths for Massachusetts occupants age 13 and older by about 5 percent. That’s roughly 10 lives saved each year, based on 2023 crash numbers.
Right now, Massachusetts has a secondary enforcement law. That means police officers can only ticket drivers for not wearing a seat belt if they’ve been stopped for another traffic violation first. It’s one of the few states that still follows that approach, which safety advocates have long argued reduces compliance.
According to IIHS, the new seat belt law calculator uses state‑by‑state data to show how policy changes could boost belt use and lower fatalities. The organization says it developed the tool using statistical models that draw on decades of safety research.
“Our new calculator gives policymakers a clearer picture of the lives they could save simply by strengthening seat belt laws,” IIHS President David Harkey said in the official release.
IIHS found that in 2023, if every state had what it calls “optimal belt use laws,” an estimated 277 additional lives could have been saved nationwide.
The organization points out that primary enforcement laws have been proven to raise seat belt use rates—often by about 10 percentage points compared with states that only allow secondary enforcement. Massachusetts’ seat belt usage rate has historically lagged behind the national average, with the most recent surveys showing compliance at around 80%, compared to roughly 92% nationwide.
Safety advocates say that’s a problem, given that wearing a seat belt dramatically reduces the risk of dying in a crash. The National Highway Traffic Safety Administration (NHTSA) estimates that lap and shoulder belts cut the risk of fatal injury in half for front‑seat occupants.
As lawmakers in Boston continue to debate ways to improve roadway safety, the IIHS calculator could provide a clearer argument for revisiting the state’s seat belt law. For now, drivers in Massachusetts can explore the new tool and see its projections for themselves on the IIHS website.
