New carriageway plans for Basingstoke's M3 junction
Plans for a four-lane carriageway through a roundabout at a junction on the M3 are to go on show.
The Highway Agency's proposals for the junction 6 Black Dam roundabout in Basingstoke also include widening all of the approaching roads.
About 6,000 vehicles use the route each hour at peak periods. The agency said it will reduce congestion.
A public exhibition will be held at Basingstoke Discovery Centre, Festival Place, between 10:30 and 17:30 BST.
Ed French, from the Highways Agency said: "This is a significant improvement for this busy junction and it will bring substantial benefits to road users, business and the general public."
The project is part of the government's £317 million pinch point programme.
The Highways Agency is working in partnership with Hampshire County Council and Basingstoke and Deane Borough Council.
Work is due to start in October and be completed by summer 2015.