The California Highway Patrol is trying to find the person who dumped hundreds of nails and tacks on a road near Woodside that’s popular among cyclists.

Officers said Monday that there were so many nails left on Kings Mountain Road that clean-up crews were forced to sweep the lanes to get them out of the way.

Cyclists are usually drawn to the road for its views and 1,500-foot climb to Skyline Boulevard.

"This is one of my favorite hill climbs," Michael Shorts said.

But riders, who are now being warned to pay close attention to the sidewalks, are afraid they are being targeted.

"It’s really frightening to be honest," Grace Chuchla said.

Chuchla and her teammates on the Stanford cycling team have seen pictures on Facebook that show dozens of nails that were scattered near the summit on Kings Mountain Road and Skyline Boulevard.

"You’re on a 20 lb. bike with a 23-millimeter wide tire," she said. "If it hits a tack, and your tire blows, you’re going to hit the pavement and it’s going to hurt."

CHP officers said that two weeks ago about 20 riders had to replace their tires after rolling over nails. No one was injured and investigators are asking for help to find the person responsible.

"Think about your own kids riding a cycle ... and getting a concussion or worse," Ken Doub said.

Many cyclists and drivers suspect that whoever is behind these incidents doesn’t want to share the country road.

"I’m sure some of the neighbors don’t like all the traffic," Maoz Friedman said. "It sucks they would go that far to discourage people from coming up."

A cyclist team is raising money to offer a reward for information that could lead to an arrest. So far, they’ve raised about $5,000 for their cause.