The Howard County Council passed a mandatory bicycle helmet law last night that industry groups said is the first of its kind in the nation.

The law, which will take effect in October, requires riders to wear helmets on all county streets and paths but does not apply to state and private roads. Violators can be fined up to $50 for a first offense and $100 for subsequent ones.

"We made history tonight," said Susan Sullivan, a county middle school teacher who helped spearhead support for the law. "I hope this will convince other communities to support helmet laws."

The council approved the ordinance by a 3 to 2 vote after stripping the measure of language that would have restricted it to children under age 16.

County Executive Elizabeth Bobo (D) has said she will "absolutely not" veto the legislation.

Mandatory helmet laws are opposed by many bicycling and bicycle trade groups. They argue that most riders will simply ignore the law or give up the activity.

"We believe that helmets are one of the most effective countermeasures for protecting bicyclists, but we don't think mandating helmet use is good public policy," said William Wilkinson, executive director of the Bicycle Federation of America.

Among County Council members, Angela Beltram (D) voiced the strongest opposition. She said the lack of federal standards for bike helmets makes her uncomfortable with mandating their use.

"If I vote for the bill I'm saying to the public that helmets are safe," Beltram said. She voted against it.

The county law requires that helmets meet voluntary standards set by the American National Standards Institute or the Snell Foundation.

Council Chairwoman Shane Pendergrass (D), the other "no" vote, complained that the law probably is unenforceable.

Council member Paul R. Farragut (D) disagreed, saying, "I think it is about as enforceable as a seat belt law or a child seat law."

After the vote, Charles C. Feaga said, "We got more than we hoped for." Feaga, the council's lone Republican, was the helmet bill's sponsor. "I want to thank those who voted for the bill for putting aside petty politics and doing something for the kids. I hope this gives some momentum to other counties to adopt similar laws."

"If we can prevent one injury with this bill, then I think it's worth the effort," said council member C. Vernon Gray (D), who joined Feaga and Farragut in voting for it.

County police have said they will ticket bicylists only as a last resort. The law allows a judge to waive fines if violators prove they bought a helmet after being ticketed.

The law's supporters said they were swayed by the testimony of doctors and injury-prevention specialists who estimated that nearly three-quarters of all bicycling deaths stem from head injuries. One study indicated that a bike helmet can reduce the risk of head injury by 85 percent. Studies also have shown that adults are far more likely to wear helmets than children.

The idea of mandating helmet use quickly won the support of many county students, particularly those at Glenwood Middle School in the western part of the county. A Glenwood eighth-grader was killed last fall when a car struck his bicycle. A similar incident the previous spring killed a Glenelg High School bicyclist who had attended Glenwood.

Glenwood students lobbied for the bill by calling area newspaper editors and testifying before the County Council.

The students said helmets are needed now more than ever in Howard County because the vehicular traffic is getting heavier on the largely rural roads near their school. The rural roads have been popular with county bicyclists, as has the extensive network of trails in Columbia.

Only New York and California have adopted laws requiring helmet use. Both states' laws apply only to bicycle passengers under age 4.

The measure also was amended to delay its effective date 150 days to give schools and community officials time to explain the ordinance to riders.

A waiting period will give stores time to stock their shelves with helmets, council members said. A spot check last week of large toy and department stores serving Howard County found a slim selection of helmets. Helmets generally cost $25 to $100.

"You've got to convince people of the need to wear a helmet before it will be palatable to them . . . . We should promote . . . it, and then see where we're at," said Wilkinson of the bicycle federation.