A one mile section of metal barrier at junction 23 has reached the end of its working life and is being replaced with a new stronger and safer concrete barrier.
The £2 million improvement scheme involves extensive excavation and construction along the central reservation, with more than 1,400 tonnes of concrete being used, and from Tuesday 1 November until Thursday 22 December two narrow lanes will be in operation northbound and southbound, with a 50mph limit in place.
Highways England is advising drivers to plan their journeys during the seven-week period of work, particularly this Saturday (5 November) when visitors travel to the Bridgwater Guy Fawkes Carnival.
The annual Bridgwater Carnival, the largest illuminated carnival in Europe, attracts up to 120,000 spectators and visitors travelling northbound are advised to access the event from junction 23 as the A38 near Hamp will be closed from 7pm on the night.
Gareth Price, Highways England emergency planning officer for the south west, said:
The carnival is a popular event in the south west and can lead to increased traffic volumes between junctions 24 and 23 of the M5, particularly between 5pm and 7pm and from 9pm onwards.
In view of the traffic management in place to facilitate the current safety barrier work, we advise all road users to allow extra time for their journeys and to check our traffic and travel information channels.
Highways England provides live traffic information via its website.
Travel information is also available by phone from the Highways England Customer Contact Centre on 0300 123 5000 and updates will be provided via Twitter.
Carnival goers can also find further information on the Bridgwater Carnival website.
Members of the public should contact the Highways England customer contact centre on 0300 123 5000.
Journalists should contact the Highways England press office on 0844 693 1448 and use the menu to speak to the most appropriate press officer.