A diversion will be in place for traffic in Findon from today while a large tree is removed for safety reasons, a county council spokesman said.
Southbound traffic on the A24 will be diverted from the Findon bypass along Long Furlong and to the A27 into Worthing between 9.30am and 4pm.
The diversion is expected to last about four days.
A limb from the tree came down in high winds last week and fell into Findon Cemetery land.
Inspections revealed the mature beech, which is growing in the verge alongside the A24, will have to be felled for safety reasons, the spokesman said.
Keeping one lane open was not an option because of the tree’s size and the need to create a safe working area for the tree surgeons, according to the spokesman.
The spokesman said every effort is being made to minimise the time the diversion is in pace and restricted hours are being used to avoid peak traffic times.
Nearby major drainage work on the north and south-bound carriageways near Findon on the A24 is progressing well, added the spokesman.
Bob Lanzer, cabinet member for Highways and Infrastructure, said: “During essential works like these, where possible we try to include other maintenance to keep inconvenience for road users to a minimum.
“In this case, these include crash-barrier repairs, footway patching, carriageway patching, litter picking, gully emptying and soakaway repairs.”
These roadworks started on September 11 and, dependent on factors such as the weather, are due to finish around September 29.
Mr Lanzer said: “We have people working on site from 7.30am to 5pm.
“Due to the nature of the works and the co-ordination of the different elements, there may be times when the site appears empty.
“However, please be assured we are making every effort to optimise the work we are doing to minimise disruption for road users.”
There will be further drainage investigations on one lane of the northbound carriageway, starting Monday, October 2, the spokesman added.
These works are to clear blockages in the drainage system.
There will be no disruption for traffic on the southbound carriageway.
To have done this as part of the major drainage works would have needed a complete lane closure from Findon to Washington, restricting traffic even more, the spokesman said.