There will be narrow lanes and a 50mph speed limit starting from today as preparation works starts to demolish the Spittleborough Access Overbridge over the M4 between Junctions 16 and 17 near Swindon.
Demolition will be carried out overnight between 19.00 hours on Saturday 17 January and 10.00 (am) on Sunday 18 September. During this time the motorway will be closed in both directions and traffic diverted.
The existing concrete bridge is reaching the end of its working life and will be replaced later in the year.
Highways Agency project manager Dave Frampton said:
“The existing structure is one of several bridges built in the early 1970s which need to be replaced as they are reaching the end of the working lives.
“Although we are fully closing the M4, we’re doing it at a time when traffic flows are lower, so that we limit any delays for road users.
“Following the demolition construction work on the replacement bridge will start in conjunction with work to install the new South Leaze Bridge nearby which was demolished in September.”
During the overnight closure the following diversions will be in place:
During the overnight closures, traffic will be diverted as follows:
Light vehicles will use the A429 and the B4042 between J16 and J17 (via Malmesbury).
Heavy vehicles will use the A3102, A4 and A350 between J16 and J17 (via Calne and Chippenham).
Further details about the closures needed to install new bridges at both South Leaze and Spittleborough will be publicised nearer the time. The narrow lanes and 50 mph speed limit will remain in place until the new bridges are installed.