COLUMBIA - Gov. Mark Sanford Thursday let a mandatory seat-belt bill become law Thursday without his signature, despite an earlier signal that he would veto it because it lacked adequate penalties.

"It's going to become law, but without my blessing," Sanford said at a news conference in his State House office. "I've got, still, real reservations about this particular idea."

He had until 11:59 p.m. Wednesday to sign the bill passed by lawmakers last week, veto it or step aside and allow it to go on the books automatically.

The governor said he decided not to veto the measure because although it has been illegal to ride unbuckled in South Carolina since 1989, police can't stop adult drivers unless they committed some other violation.

"There is no other law that my folks could find," Sanford said, "wherein we have a specific prohibition against law enforcement enforcing a law that's on the books."

He said, "My belief is you ought to have fewer laws. The laws that you have, though, ought to be enforced."

The new law, which carries a $25 fine, goes into effect in January. Officers will be able to stop any motorist they see not wearing a seat belt. The law's supporters hope it will raise the level of seat belt use in South Carolina -- currently one of the lowest in the nation at 59 percent -- and thereby reduce the number of deaths and serious injuries in wrecks. The S.C. highway death rate is among the highest in the U.S., and 75 percent of those killed had not been buckled up.

However, Sanford said, "I would anticipate that this bill will not yield the results that people are hoping for."

Unlike North Carolina, where court costs drive the price of being caught unbuckled to $75, South Carolina would charge only a flat $25.

And unlike the mandatory seat belt laws in North Carolina and 20 other states, S.C. law enforcement officers would not be able to use "Click It or Ticket" roadblocks to catch people who failed to buckle up.

National highway safety experts say such roadblocks, and the publicity campaigns that states use to advertise them, are what make seat-belt laws effective.

Sanford said the best way to make people buckle up would be to allow people being sued in cases involving injuries from wrecks to introduce evidence in court that the injured person wasn't wearing a seat belt. Such evidence could be used to reduce the amount of damages awarded.

He said he would veto any future legislation strengthening the seat belt law unless it includes such admissibility.

"I think it's a free market way of solving the problem," Sanford said. "I think everybody ought to wear seat belts, but it ought to be personal judgment."

Are You Buckled?

• The new law goes into effect in January.

• Officers can stop any motorist they see not wearing a seat belt.

• The fine is $25.