Log 62: Grand Theft Horse? - S1-E16
Continuity mistake: When Reed and Malloy are chasing two armed robbers, one of the robbers shoots at their car and a bullet damages the windshield. But after the incident, as they resume patrol, the windshield is undamaged.
Continuity mistake: The unit says 1w20 then later says 1w30. (00:25:40 - 00:26:40)
Continuity mistake: In the opening scene, an officer is yelling at Reid for trying to give him a dog. There's a gun belt hanging on the locker next to Reid, Malloy comes in and it's still there. Next angle, it's gone.
Answer: You probably need to be more specific about which car or episode you're talking about, but if I had to guess, it sounds like you're talking about "curb feelers." Most people have to park on the right side of the road (passenger side), so the wires or springs would make a noise when they hit the curb, letting the driver know they're close enough to the curb without hitting the tire against the curb.
Bishop73
S5 Ep5 "Training Wheels": Adam 12 stops a VW van. Their Matador car has a curb feeler on the left front of the car.
Correction: That's the right-hand side of the car.
Probably for one way streets. When they were popular, I saw them on front and rear. They were the mustaches and eyebrows of the day.