A Telford councillor hopes the signs will become a permanent part of Ironbridge's flood plan after motorbikes had been seen crossing the pedestrian-only bridge.
Councillor Carolyn Healy witnessed motorbikes attempting to cross the bridge, which has been closed to traffic for 89 years, on Thursday, with another incident reported on Friday.
The Wharfage is currently closed because of the flood barriers, and Councillor Healy reasoned that drivers may see the bridge as a short-cut past the diversions.
She said: "I don't really know why motorists might think it's a good idea, because it doesn't save you any time. But maybe they don't really know the area and think it's a quicker way of getting through.
"Hopefully the signage might at least make people more aware, and keep it safer for pedestrians.
"It's important that people know the Iron Bridge is not for motorised vehicles, and that all motorised vehicles need to follow the normal roads to get to our car parks."
Despite the Wharfage being closed to vehicles, businesses and visitor attractions along the road remain open, and can be reached on foot.