Speed limits are set to be introduced along a stretch of the A27 road in Brighton and Hove.
The restrictions come as part of safety preparations for the Stanmer Park Beyond Boundaries Festival.
National Highways has confirmed that a 50mph limit will be enforced around the clock on affected sections of the road.
The speed reduction takes effect on Thursday, 24 September.
The measures apply to both directions of travel along the A27 between points near the Ditchling Road and B2123 overbridges.
Entry and exit routes at the Coldean interchange connecting to the A270 from Stony Mere Way will also fall within the restricted area.
The purpose of the temporary speed reduction is to protect members of the public attending the festival.
Traffic signs will be positioned to inform drivers of the changed speed limits.
The restrictions are scheduled to remain in operation until the event concludes.
Those seeking further information about the limitations should contact the National Highways Customer Contact Centre.
