New regulations have been introduced to stop people selling cars and leaving advertising hoardings near motorway bridges in Birstall and Birkenshaw.
A traffic regulation has now come into force following a campaign by ward councillors.
Coun Liz Smaje (Con) said they had been inundated with complaints.
She said: “Cars for sale on the bridges are an eye-sore and the advertising a danger for vehicles travelling on the motorway. They are very unpopular with local residents and had to be stopped.
“I, and my ward colleagues, are delighted that we have finally been able to secure legal support to remove the offenders.”
It is now illegal to park on bridges crossing the M62 at Bradford Road and Whitehall Road in Birkenshaw and Fieldhead Lane in Birstall.
Double yellow lines have been introduced and any offending vehicles will receive tickets.