In a statement, West Sussex County Council said the project will make motorists ‘feel safer’ and improve visability.
However it will see a eight weeks of road closures affecting the key route.
Middleton-on-Sea Parish Council Chairman Shirley Haywood welcomed the project.
“At long last work to improve the Comet Corner junction is about to start,” she said. “The drainage works also carried out now are extremely welcome given the appalling flooding experienced on this road in 2012.”
However Ms Haywood added: “The parish council understands the preferred solution of traffic lights at this busy junction cannot be implemented.
“This is because the proposed cost of £2.5m is well outside the £375,000 budget at present available to the County Council.”
Expected to take eight weeks, the £550k scheme will see the bend in Worms Lane widened and an extension to the deceleration lane exiting the A259 into Worms Lane, along with upgrading drainage.
A temporary closure order has been made for the B2132 Yapton Road and Yapton Road/Worms Lane from January 9 to April 7 to allow the work to be carried out.
The council said that ‘a section of Worms Lane needs to be closed for the first two weeks of the project,’ during which time a diversion will be in place, and that one it re-opens Yapton Road ‘will close for the remaining six weeks’.
WSCC’s Cabinet Member for Highways and Transport, Bob Lanzer, said: “We have planned both the junction improvements and the drainage work at the same time to minimise disruption.”
The council’s statement explained the work will take place during daylight hours, ‘except for two nights when a new road surface will be laid’, and that ‘two-way traffic will be maintained at all times along the A259 during the works’.
The scheme’s £550k total is made up of the highway improvements cost of £375k, funded by developers’ contributions, and £175k by the council on drainage work.