IIHS launches seat belt law calculator for US states

The Insurance Institute for Highway Safety (IIHS) has launched an online calculator showing how changes to seat belt laws would affect belt use and fatality rates in each US state. The organisation estimates 277 lives would have been saved in 2023 if every state had optimal seat belt laws.

Seat belt laws vary across the 50 states and the District of Columbia, with 16 states not requiring adult passengers to use belts in the rear. Laws also differ according to enforcement type, with primary enforcement allowing police to stop a vehicle solely for failure to buckle up, while secondary enforcement only permits citations if the driver has been pulled over for another violation.

IIHS says failure to use a seat belt remains a significant factor in road deaths. Among people aged 13 and older killed in crashes while riding in passenger vehicles in 2023, only 45% were confirmed to be using belts.

In a statement, Chuck Farmer, Vice President for Research at IIHS, said: “This calculator will help advocates and policymakers understand the safety benefits a state can reap with simple legislative changes.”

Vehicle technology is also helping increase belt use. IIHS began rating belt reminders in 2022, and says 71% of 2025 model year vehicles earned a good rating, compared with 16% of 2022 models. The organisation says persistent visual and audible reminders beyond the 4-8 second federal requirement are highly effective at changing behaviour.

Source: IIHS