Drivers are being warned that there could be delays in King’s Lynn this weekend because of traffic light problems.
Work to the power supply at County Hall in Norwich means the computer co-ordination of the lights will be interrupted.
The lights will continue to work, but the normal changes at different times, according to the volume of traffic, will not be in operation.
A statement from the county council said the Urban Traffic Control computer would be suspended while the work was carried out.
The power supply at County Hall is being updated and the work will also affect the traffic lights in Great Yarmouth, but not in Norwich.