Residents and road users are advised that five-way traffic lights are needed on the MountainAsh Cross Valley Link bridge on Monday night (April 7).
To minimise disruption, the work has been scheduled for the evening and overnight, from 7pm to 6.30am.
The temporary signals will cover the Miskin Road and Cardiff Road junctions and the entrance to the industrial estate, but will not be required on the A4059 junction.
These arrangements are needed for remedial works, including replacing a bridge parapet section.
The work is scheduled to be completed before the peak travel period on Tuesday morning.
However, there is the potential that a second night of work is needed on Tuesday, April 8, depending on progress.
