Work is scheduled to begin next week to replace sections of the barriers on the M5 sliproad at Junction 18 near Avonmouth.
The scheme involves removing the current steel restraint barriers and replacing them with concrete barriers.
The project is due to start on 3 August and is scheduled to be completed by 18 August.
The majority of work will take place overnight from Monday and Friday between 8pm and 6am, with the southbound sliproad being closed completely during these times.
Daytime lane closures will be in place for the first two days of works.
Highways Agency project sponsor Dave Frampton said: "The existing barrier has reached the end of its life and needs to be replaced to maintain safe and reliable journeys on this vital route."
Diversion routes will be in place while night time closures occur.
(LM)
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