Cyclists have been warned to be aware after vandals set a trap on an A259 cycle path.
Adam Bell, a volunteer at Sustrans cycling charity, was clearing the path along the A259 between Littlehampton and Flansham when he came across four screws protruding from the tarmac.
Each was sticking 1-2cm out of the ground and Adam believed they were put there intentionally to injure cyclists.
“This was a malicious act," he said, adding that the hazards had appeared in the last month between Comet Corner and the Climping Roundabout.
"They are targeting cyclists or trying to target runners. If someone was running along they could catch their foot and cyclists could be hurt or worse.
"It’s obviously someone who hasn’t got any empathy."
Adam said several of the screws were bent over from thick bike wheels, but cyclists on more narrow wheels could easily be knocked off into the busy road.
While he managed to prise one out with a wrench, he has had to return to remove the other three with a claw hammer.
He had spoken to workmen to see if they could have been put there to fix a sign to the floor, but was told they would use unfixed A-frame signs.
This kind of incident is not uncommon for cyclists, he said, who are regularly targeted by trap-setters.
He pointed to instances of tacks spread along cycle paths and even lines being stretched across them to guillotine people on bikes and runners.
"They are human beings," he said. "Just because they are on two wheels rather than four, they are still people."
While he admitted it was a difficult matter to police, he hoped highlighting this particular act could help raise awareness and deter any similar incidents in the future.