Taxi driver unions are to oppose plans to create a vast 20mph area.
Brighton and Hove City Council’s transport committee signed off on plans to introduce the restrictions on more than 500 streets between Sackville Road, Hove, in the west and Freshfield Road, Brighton, in the east.
Only Sackville Road, Old Shoreham Road and the A259 seafront road will be immune from the new limits, which will come in from April.
But the GMB union, which represents about 1,800 taxi drivers in the city, is unhappy it was not consulted after the proposal was unveiled earlier this year.
Representatives have told council chiefs the union will oppose the traffic order when it is advertised in the coming weeks.
They added it will also seek legal advice to see if the local authority had complied with its lawful responsibility to consult.
See the latest news headlines from The Argus:
- Two pupils excluded after classmates alert teachers they had knives in their bags
- Slice of Brighton's prime real estate goes on the market for "just" £50m
- Fresh hope in fight to save 145-year-old Brighton pub from development into flats
- Family claim police officers just sat and watched as 19 traveller vehicles moved on to park
- £250,000 to be spent on five police drones - but purchase sparks privacy concerns