The busy road's being made two lanes in both directions between Segensworth and Titchfield - it's due to take 18 months.
Southampton Cruise Business Booming
Figures out show 1.5 million people passed through Southampton last year, making it Europe's busiest turnaround port.
Each ship that comes into the port is thought to be worth around £2.5 million to the city's economy and it's good news for employment too; the industry supports more than 11,000 jobs across south east England.
The figures, from the Cruise Lines International Association show spending on cruises in the U.K. last year rose 3.7% to £2.49 billion, and the industry's contribution to the economies of Europe was also up in 2012 - rising 3.4% to £13.15 billion.
Britons took more than 1.7 million cruise holidays last year, with the UK staying Europe's biggest cruise market with a total share of 27.7%.
CLIA UK and Ireland director Andy Harmer said: "These figures demonstrate the continued and growing strength of the British cruise market."
Police want to trace man after 11-Year-Old Approached Near Oasis Academy
Family Appeal Is Shared Online After 14-Year-Old Missing Since Friday
Exceptionally Rare Locker Key Sells For Record Price At Auction.
Recently Played Tracks
Deposit £10 to get a £40 Welcome Bonus - That's £50 to play bingo, slots and more!*
Over 50 tracks to make you feel-good. New album out now...
Find your local four day weather report here.
What's happening on the roads where you are?
Make Heart the soundtrack to your day and you could be a winner with great prizes up for grabs throughout the day.
Find out more about some of the companies advertising on Heart.
Get some great ideas on how to advertise your business on radio, online and on mobile.