The temporary move has been made to ensure that Portsmouth does not face the crisis recently seen in Kent.
Hampshire County Council said;
“There’s a new speed limit of 30mph on the A31 between Winchester and Alresford.
The change is for the safety of road users and traffic marshals as the westbound lane of the A31 is used temporarily as a short-stay triage point for EU-bound freight traffic travelling to Portsmouth International Port to check they have the correct ‘border-ready’ documentation in place.
The A31 will be kept open in both directions at all times for traffic using the eastbound lane.
If you’re using this route for your essential journeys, please plan ahead and allow extra time.”