Saboteurs are being blamed for switching speed signs to bamboozle drivers with conflicting messages.
The signs state maximum 20mph and 30mph as drivers enter Austin Avenue in Plymouth, Devon - and as they exit, the speed signs are reversed.
Plymouth City Council said it placed them facing the right way and someone had "deliberately turned them round".
It said the signs would be changed back and fixed so they were less likely to be tampered with.
Austin Avenue was one of a number of roads in Plymouth which got new signs after the speed was cut to 20mph maximum.
Lorraine Couling, who works in a shop on the corner of the road, said: "They are are very confusing, you are not sure if you have to do a 30 out or 30 in, or 20 in or 20 out."