Plans for the proposed A31 widening scheme at Ringwood are set to go before the public.
Options for introducing a third lane westbound – between Ringwood and Verwood turn off – will be presented at a public consultation at the Gateway in Ringwood on June 9-10, town councillors have confirmed.
Plans currently suggest works could begin in 2019 and be completed sometime in 2020.
A Highways England spokesman said: “Improving the A31 near Ringwood will bring real benefits to people living, working and driving in the area, and we have been making good progress in developing our plans.
“We look forward to hearing what people have to say about the plans when we pit them to the public later this year.”
Engineers have had to assess whether or not to introduce new speed limits. They have also had to work around the demands of the River Avon.
Councillor Christopher Treleaven told the Daily Echo: “Natural England has quite strong demands for the salmon to get upstream, just like the newts had to be accommodated on the A338.
“Highways have looked at several different ways at doing it. It does involve adding an extra lane to the bridge.”
As part of the consultation, Highways are also considering whether or not to close West Street from accessing the A31 and whether or not to introduce a 50mph speed limit.
“The congestion is caused by rush hour traffic coming from Southampton, Salisbury and Christchurch all coming together,” Cllr Treleaven added.
“Highways tell us on the one hand we have got all the problems with West Street properties and, on the other hand, they have got the issue that traffic will be much faster.
“They have to balance that. Hopefully by June 9 they will have come up with one view or another. Highways have not given us any hint about whether they will keep the road at 70mph.
“Highways are interested in keeping the trunk road flowing.
“For the 14,000 people living here it is about getting to where they want to go safely and how to combine local access with a major trunk road. That’s the tricky bit.”