The busy road's being made two lanes in both directions between Segensworth and Titchfield - it's due to take 18 months.
Concern Grows For Weymouth Sailor
The family of a sailor missing from Weymouth say they're desperate for news, four days since he was last seen.
Geoffrey Cole was planning to sail to Swanage on Saturday morning.
His boat was found by French coastguards washed ashore in the area of Griz Nez near Calais and Boulogne.
Inspector Bob Jacobs, of Dorset Police, said:
''We are growing increasingly concerned for Geoffrey and are anxious to establish his whereabouts.
His family are desperate for him to return to them safe and well.
I am appealing for anyone with any information to Geoffrey's whereabouts to get in touch at the earliest opportunity.
Anyone with any information should call Dorset Police on 101, quoting incident number 23:159''.
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