Work by Highways England to create a toll-free journey for drivers heading into Wales will start on Friday 14 December.
Both bridges over the Severn river in to Wales will undergo changes to create a route that means drivers will no longer have to stop to pay the toll.
Severn Bridges General Manager, Hannah Milliner, said: “Work is needed to make sure that drivers can safely travel across the bridges without stopping to pay a toll, or waiting for a barrier to be raised. The weekend we have chosen avoids peak period traffic and also means that the work will be complete so that drivers can make journeys free of charge over the festive period.
“We would like to thank drivers in advance for their patience while we carry out this work and to ask them to plan ahead for any journeys they are considering.”
Friday 14 December
From 9am on 14 December three toll lanes will be closed on the M4 Prince of Wales Bridge to allow work to start.
The M48 bridge will operate as usual.
At 8pm the Prince of Wales Bridge will be fully closed westbound and drivers will be diverted via the M48 bridge.
Saturday 15 and Sunday 16 December
This same pattern will continue over the weekend with the bridge running with three toll lanes closed from 6am to 8pm on Saturday and 6am to 7pm on Sunday.
Overnight the bridge will be fully closed westbound and drivers will be diverted via the M48 bridge.
Monday 17 December
On Monday 17 December, the Prince of Wales bridge will reopen with three free flowing lanes. These will be narrow lanes with a 50mph speed limit to ensure the safety of drivers.
Shortly after the Prince of Wales bridge reopens on 17 December, the M48 bridge will be fully closed westbound, reopening on the morning of 19 December with two free flowing lanes. These will be narrow lanes with a 50mph speed limit to ensure the safety of drivers.
Further work will be carried out in 2019 to return both routes to a three lane motorway with the usual 70mph speed limit.
Hannah added: “This is a significant piece of work which is far more complex than simply removing toll booths. We want to make sure that journeys can be completed safely and free of charge by the end of the year and will then focus on the next stage of work.”
Other changes taking place include the closure of the M4 Rogiet Tag office.
Information for Tag holders has been provided directly to account holders, a summary can be found on the Account closure page..
Drivers can keep up to date with closures via the Severn Bridge website, all closures will also be published on the Maintenance and Closures page.
Details can also be found on Twitter by following @highwaysswest.