Only one-way traffic is allowed in Uckfield High Street now that road works have reached the section between Library Way and Church Street.
This means that traffic which was previously allowed to turn left on exiting the Luxford car park via Library Way now has to turn right.
A spokesman for the Town Centre Reinvestment project board said: “The traffic order put in place before this stage of the work began did prohibit turning left out of Luxford car park, however to try and assist motorists, until now we have continued to allow motorists to turn left.
“Now the work has moved further up the High Street, we do need to enforce this order so cars can now only turn right out of this car park.
“At present there is a closure of Civic Approach which is due to finish in the next few weeks, which means that there will not be any two-way traffic at any point in the High Street at this time. Although the car park is open at Library Way, motorists will need to follow the one-way system on exiting.
“As the scheme continues we will always try to allow as much two-way flow as we can for limited times to help motorists, but during certain phases of the work this will not be possible.”