COLUMBIA — It's official: Drivers must share the roads with cyclists, under a law Gov. Mark Sanford signed Tuesday.

"Cyclists are traffic and motorists have a responsibility to be on the lookout," said Natalie Cappuccio Britt, executive director of the Palmetto Cycling Coalition.

The law, which is now in effect, makes it a crime to harass, taunt or throw something at a bicyclist. Procedures for sharing the road, and when and where cyclists should enter the roadway, are spelled out in the legislation, which has been in the works for two years.

Cyclists can use the road, shoulder or special bike lanes, the legislation says. It also makes signaling for bicyclists simpler by, for example, allowing them to point in the direction they're heading.

Jackie Hughes of James Island said she can foresee the law leading to problems and more unsafe conditions on the road.

"They cause a hazard to the cars," Hughes said of cyclists. "You're behind someone doing 5 miles an hour and you've got cars lined up. You're risking an accident and your life when you pass."

Sanford was joined by cyclists and advocates at Outspokin' Bicycles, a shop about three miles from the Statehouse, for the bill signing. The issue is one of equality, said Sanford, himself a cyclist.

"It's a principle much larger than bicycles, cars or roadways," he said.

The law comes at a time when gas prices have hit $4 a gallon, and South Carolinians are looking for alternatives, he said. It is also a statement about enhancing quality of life and leading healthy lifestyles.

Cappuccio Britt said efforts to pass a law clarifying cyclists' rights and attempting to make the roads safer and more accessible to bikes began following the death of Garrett Patrick Wonders of Goose Creek.

Wonders, 25, was struck by a pickup truck in 2004 during a training ride just south of Moncks Corner. He was regarded as the fastest cyclist in the Lowcountry, and hoped to compete in the U.S. Olympic Team trials.