As state legislatures move toward adjournment, proponents argue that such laws save lives, while opponents counter that they are an unnecessary government intrusion.

For states confronting deep budget gaps this year, the debate has an added resonance: Transportation grants that Congress made available to states that enact mandatory seat belt laws expire June 30.

Florida and Arkansas recently enacted such laws, and at least four other states are considering similar measures.

Twenty-eight states and the District of Columbia now have "primary" seat belt laws, which allow officers to stop people solely for not wearing seat belts; 21 states have "secondary" laws, which permit police to ticket motorists for not wearing seat belts only if they stop them for another offense. New Hampshire has no seat belt law for adults.

Legislators in Minnesota, Missouri, Vermont and Wisconsin are debating primary seat belt laws; measures to strengthen seat belt laws failed this year in states including Colorado, Kansas, Nevada and New Hampshire.

Financial pressures have left states more open to the idea of strengthening seat belt laws this year, says Melissa Savage, a transportation analyst at the National Conference of State Legislatures.

Florida is eligible for $35 million in federal funds, Arkansas for about $9.5 million.

"The money availability in a time of financial crisis is an important factor," says Lilliard Richardson, a University of Missouri professor whose 2006 study found that primary seat belt laws increased usage rates by 10% and cut driver crash fatalities by 5.1%.

James Baxter, president of the National Motorists Association, which opposes any seat belt laws as unnecessary police intrusion, says the federal incentive is the only reason states are passing primary laws this year. "The real motivation is the money," Baxter says.

Nationally, seat belt use is at a record level of 83%. However, the National Highway Traffic Safety Administration estimates that in 2007, more than 5,000 crash deaths would have been prevented if occupants had been wearing seat belts.

Arkansas state Sen. Hank Wilkins IV, a Democrat, sponsored a primary law and says he helped push it through by building a broad-based coalition of supporters, educating people about the dangers of not wearing seat belts and being persistent.

Wilkins says the federal incentive money "probably swayed maybe a couple of votes."

Jonathan Adkins, a spokesman for the Governors Highway Safety Association, says only 10 states have reaped a share of $498 million Congress set aside for states that upgraded to primary laws.

The most closely watched legislative debate over seat belts this year was in New Hampshire, where a primary seat belt law was passed by the state House of Representatives. The Senate changed it to a secondary law. Last month, the state Senate postponed final action.

"I don't see why we need it," says New Hampshire state Sen. Bob Letourneau, a Republican who opposed the measure and objects to the federal incentive money. "It's a handout from the federal government, and that doesn't sit well with me. We're doing better than the national average (on seat belt usage) and better than some other states that have primary laws, and we're below the national average in fatalities."

State Rep. Sally Kelly, a Democrat who sponsored the seat belt law that passed in the state House, says she once opposed seat belt laws, believing they conflicted with her state's commitment to rugged independence, epitomized by the state motto "Live Free or Die."

Then she says she learned the state bears an "overwhelming" financial burden for those injured in crashes. Also, she says, modern vehicles are designed to crumple in the front while protecting the driver and passengers and seat belts are an integral part of that design.

Kelly says her informal survey of 200 voters in her town of Chichester found that 68% supported her legislation. "The silent majority wants a seat belt law," she says.