On March 3, 2026, the Insurance Institute for Highway Safety launched an interactive calculator showing exactly how many lives each state could save by upgrading its seat belt laws. The bottom line: if every state adopted optimal belt laws, 277 Americans who died in 2023 would still be alive today.
- IIHS launched a free seat belt law calculator on March 3, 2026, showing state-by-state fatality impact
- 277 lives could be saved annually if every state had the strongest seat belt laws
- New Hampshire is the only state with NO front seat belt law — and could cut occupant deaths by 8.9%
- 16 states still have no rear seat belt requirement for adults
- States with weaker belt laws have higher bodily injury claim rates — raising premiums for all drivers
The Insurance Institute for Highway Safety launched a first-of-its-kind online calculator on March 3, 2026, revealing exactly how many lives each state leaves on the table by failing to strengthen its seat belt laws. The verdict? Across the country, 277 people who died in traffic crashes in 2023 would have survived if every state had optimal seat belt legislation in place.
For drivers, this isn't just a public health story. Weak seat belt laws drive up bodily injury claim rates — and that affects what every driver in those states pays for auto insurance, whether they buckle up or not.
How the IIHS Calculator Works
The IIHS seat belt law calculator uses statistical models built from decades of published research on how different types of laws affect belt use and crash outcomes. Users can select a state, adjust its seat belt law provisions, and instantly see the projected impact on fatality rates.
"This calculator will help advocates and policymakers understand the safety benefits a state can reap with simple legislative changes. For the 22 jurisdictions that already have the strongest provisions in place, it shows the cost of any potential backsliding," said Chuck Farmer, IIHS vice president for research.
The tool reflects a key distinction in how seat belt laws work: primary enforcement allows police to pull over a driver solely for not wearing a belt. Secondary enforcement means officers can only issue a seat belt citation after stopping a driver for a separate violation. The difference in compliance — and in crash outcomes — is significant. Currently, 34 states and the District of Columbia have primary enforcement for front seats, but only 21 extend that to rear seats.
States With the Most to Gain
New Hampshire stands apart from every other state in the nation. It is the only state that does not require front-seat belt use at all. According to the IIHS calculator, if New Hampshire enacted a comprehensive belt law covering all seating positions with primary enforcement, it could cut passenger vehicle occupant deaths (ages 13 and older) by 8.9%.
Other states have partial laws — front-seat requirements without rear coverage, or secondary enforcement rules that limit police action — and the calculator puts hard numbers on what those gaps cost.
| State | Current Gap | Projected Death Reduction | What Change Is Needed |
|---|---|---|---|
| New Hampshire | No front or rear belt law | 8.9% | Enact primary enforcement law for all seats |
| Nebraska | Front seat only; secondary enforcement | 6.6% | Add rear seat requirement + primary enforcement |
| Montana | Requires all seats; secondary enforcement only | 6.4% | Move to primary enforcement |
| Virginia | Secondary enforcement | 5.9% (~33 lives/year) | Move to primary enforcement |
| Georgia | Primary front; no rear seat law | 0.7% overall; 12% rear-seat deaths | Add rear seat requirement with primary enforcement |
The pattern across the data is consistent: the stronger the law and the more actively it's enforced, the higher the belt use rate — and the lower the body count. According to IIHS, only 45% of people ages 13 and older who were killed in passenger vehicle crashes in 2023 were confirmed to have been wearing a seat belt.
The Insurance Connection: Your Premium Pays for Others' Choices
Here's the part that hits your wallet: seat belt laws don't just affect the people who skip the buckle. They affect every driver in the state through auto insurance premiums.
IIHS's affiliated Highway Loss Data Institute (HLDI) tracks bodily injury claim rates by state. States with lower seat belt usage — typically those with weaker enforcement laws — consistently show higher bodily injury (BI) claim rates per insured vehicle. When more crashes result in serious injuries rather than minor ones, insurance payouts increase. Those costs get spread across all policyholders at renewal time, regardless of whether they personally buckle up.
If you live in a state with secondary enforcement or no rear seat belt law, you may be paying more for auto insurance than drivers in states with stronger laws — even if you always wear your belt. Weak seat belt laws are a systemic cost driver baked into state-level insurance pricing.
The national seat belt use rate is approximately 91.9%, according to NHTSA's most recent data. But that number masks wide variation. States at the bottom of the usage rankings tend to cluster around states with the weakest laws — and the highest per-capita injury claim rates. New Hampshire, unsurprisingly, sits near the bottom of national usage rankings.
"Studies have consistently shown that requiring belts can sway many holdouts and that laws with primary enforcement are more effective than those that allow only secondary enforcement." — IIHS press release, March 3, 2026
What You Should Do Now
You can't change your state's laws overnight, but you can protect yourself, your passengers, and your insurance rates starting today.
Buckle everyone in the back seat, always
Rear seat belt laws are missing or weakly enforced in many states, but that doesn't mean rear passengers are safe unbelted. In a crash, an unbelted rear passenger becomes a projectile that endangers everyone in the car. Make it a non-negotiable rule.
Check your state's current laws using the IIHS tool
Visit the IIHS seat belt law calculator to see where your state stands and what the projected impact of stronger laws would be. It takes 30 seconds.
Compare your auto insurance rates
If you're in a high-BI-claim state with weak belt laws, you may be paying above-average rates. Shopping your coverage annually — especially before renewal — can offset systemic premium pressures you can't control at the legislative level.
Looking Ahead: Vehicle Tech as a Stopgap
IIHS isn't waiting on legislatures alone. The organization began rating seat belt reminder systems in 2022, which prompted rapid improvements from automakers. About 71% of 2025 model-year vehicles evaluated earned a "good" rating for their belt reminder systems — up dramatically from just 16% of 2022 models.
Still, the average vehicle on the road today is over a decade old. It will take many years before improved belt reminder technology is widespread enough to meaningfully shift national usage rates. In the meantime, the IIHS calculator makes the case plainly: legislative changes remain the fastest, highest-impact tool available. The 277 lives the calculator identifies aren't hypothetical. They're a floor estimate of what stronger laws could deliver, based on what peer-reviewed research already shows works.
Frequently Asked Questions
Primary enforcement means a police officer can pull over a driver and issue a ticket solely because a passenger isn't wearing a seat belt. Secondary enforcement means officers can only cite a belt violation after stopping a driver for an unrelated infraction. Research consistently shows primary enforcement leads to higher belt use rates.
Not necessarily. As of 2026, 16 states have no rear seat belt requirement for adult passengers. Use the IIHS seat belt law calculator to check your specific state's laws and enforcement type.
Yes. States with lower seat belt usage rates tend to have higher bodily injury claim frequencies per insured vehicle, according to HLDI data. Insurance companies price premiums partly based on statewide loss experience, so weak laws can increase costs for all drivers in that state — not just those who don't buckle up.
New Hampshire has the weakest seat belt laws in the nation — it is the only state that does not require front-seat belt use at all. It is also one of 16 states with no adult rear seat belt requirement. According to the IIHS calculator, strengthening its laws to optimal levels could reduce passenger vehicle occupant deaths by 8.9%.
The calculator is available for free at iihs.org/research-areas/seat-belts/seat-belt-law-calculator. You can select your state and see how different law changes would affect belt use rates and fatality projections.
- IIHS Press Release — IIHS Calculator Shows How Better Seat Belt Laws Can Boost Safety in Each State (March 3, 2026)
- IIHS Seat Belt Law Calculator (Interactive Tool)
- Repairer Driven News — IIHS Launches Online Tool Showing How State Seatbelt Laws Impact Death Rates (March 4, 2026)
- Carrier Management — IIHS Seat Belt Law Calculator Coverage (March 3, 2026)
- NHTSA — Seat Belt Use in the United States (2023 data)
- IIHS Research — Seat Belts Overview and Belt Reminder Ratings