A busy bus lane along the A259 coast road is to be enforced for the first time since it was installed in 2008.
East Sussex County Council started sending warning letters to drivers using the lane on the A259 in Telscombe Cliffs this week.
The council is using digital cameras to enforce the rules which are in force 24 hours a day.
After the warning period is over – which the council said would only run for “a short period of time” – anyone caught will be fined £70.
Councillor Claire Dowling, the council’s lead member for transport, said: “The misuse of bus lanes affects journey times for passengers and the reliability of public transport as well as being frustrating for those motorists who follow the regulations.
“Enforcing these bus lanes on such a key coastal route will help to ease congestion and improve air quality by encouraging people to make use of the more reliable bus services.”
The bus lane runs west along South Coast Road from the junction of Ambleside Avenue to the border of Brighton and Hove.
It is mostly used by services run by Brighton and Hove Buses, including the 12, 12X, 13 and 13X.
Bus company commercial director Nick Hill said: “We’re glad to see local bus lanes being enforced.
“Local bus lanes help us provide even better services for the local community and enforcing them helps us keep them clear for our drivers and keep our buses reliable.”
The westbound bus lane stops briefly in Saltdean but restarts from Saltdean to Rottingdean. That stretch of road is overseen by Brighton and Hove City Council and is enforced.
The county council said that revenue from penalty charge notices would be used to cover the cost of the installation, maintenance and running of the scheme.
Any surplus income from fines would be reinvested in local transport schemes.
Another stretch of the A29 is to be enforced using digital cameras from the start of Grand Parade in St Leonards to the westernmost turn-off for Warrior Square.