Sizewell C related Traffic Management & Road Closures
See below for Sizewell C current and up and coming road closures and traffic management:
Road Closures
Willow Marsh Lane, Darsham is closed until June 2026 to enable the construction of the Northern Park & Ride roundabout and site. Diversion in place via Walpole Road, A144, A12.
Abbey Lane, Leiston is closed until January 2027 to enable the construction of the new railway line. Diversions are in place via Harrow Lane, Hawthorn Road and Pretty Road.
Two full-weekend closures of the junction at Abbey Road and Lovers Lane will take place from 12-15 December and 19-22 December. Diversions are B1069, A1094, A12 and B1122.
A night-time closure is in place along Lovers Lane and Valley Road from the 22 October to 20 December 20:00 – 05:00. This to enable the installation of power cables, with daytime two-way traffic lights in place. Diversion via B1122 and King George’s Avenue.
Church Road, Theberton, is closed until 21 November by Scottish Power to carry out a Sizewell C and Scottish Power combined mitigation scheme at Theberton.
Kettles Lane, Benhall, is closed until June 2026 for the construction of the Friday Street roundabout.
Littlemoor Road, Middleton, will be closed from 17 November 2025 and is not expected to be reopened.
Closures will be in place along the B1078 on the following dates to facilitate the delivery of Sizewell C road safety mitigation scheme:
| Date | Closure | Diversion Route |
| 15 to 17 November | A140 between its junction with Buck’s Head Lane and the A14. | A14, A1120, A140 and vice versa |
| 17 November to 20 November | B1078 between its junction with B1079 (Otley) and High Road (Swilland) | B1079 and B1077 and vice versa |
| 18 November to 6 December | B1078 between its junction with Cooper Road (Coddenham) and High Road (Swilland) | B1079, A1120, A140, B1078 and vice versa
Or B1079, A1120, A140, A1214, A14, A1156, B1077 and vice versa
|
| 3 December to 17 December | B1078 between its junction with B1079 (Clopton) and Lodge Farm Lane (Letheringham) | B1079, A12, B1078 and vice versa. |
| 13 December to 16 December | B1079 between its junction with High House Road (Otley) and its junction with the Access road from B1079 to Mount Pleasant Farm (Clopton) | B1077, A124, A12, B1078 or B1079 and vice versa |
An overnight road closure of the A12 Northbound will be in place to allow white lining and removal of temporary road studs and other traffic management associated with the AIL Layby works from 5 to 6 December between the hours of 20:00- 05:00.
The A12 will be closed at the junction with the B1122 at Yoxford throughout the weekend of 5-8 December, from 8pm Friday 5 December -5am Monday 8 December. Diversion route A1145, A146, A143 , A140, A14 and A12.
The B1122 Middleton Road will also be closed at night time from 8-11 December and 15-18 December – from 8pm-5am. Diversion route B1122, B1069, A1094 and A12.
Buckleswood Road will be closed from 17 November until 31 January 2026. Diversion route Buckleswood Lane, B1119 and B1122.
Traffic Management
A12 single lane closure northbound along the dual carriage way from Ufford Road to the Wickham Market Slip Road. Expected to be in place until 6 December 2025.
A12, Friday Street, varying traffic management is in place, including lane closures and traffic signals until June 2026 as part of construction of the new roundabout.
B1122 off peak traffic signals implemented by Scottish Power at Theberton to deliver improved pedestrian footway 22 September to 21 November.
Sizewell C is also currently implementing short-term night time traffic management associated with the delivery of the Sizewell C countywide highway signs throughout the month.
Two-way traffic lights on the A12 north of Town Farm Lane: This will be in place from 17 November – 12 December 2025. This is to enable trial holes and Cadent Gas to carry out essential works to divert a gas main.
Scottish Power Renewables will have two sets of two-way traffic lights on Sizewell Gap Road from 13 October until 12 December.
A12 slip road, next to the Southern Park Ride site: Traffic lights are in use to ensure safe working zone for construction of the site entrance works. These will be in place until 12 December 2025.
Traffic lights on the A12 north and B1122 Middleton Road on nights for construction of the new road and kerb alignment for the Yoxford roundabout from 3 to 18 December between the hours of 19:00 -05:00.
Two-way traffic lights on the A12 southbound at Friday Street at night to undertake excavation in the verges, 19 to 21 November between the hours of 20:00 - 05:00.
Two-way lights on the B1122 near Middleton, 24 - 28 November (09:30-15:30) for trial holes to locate utility services.
Multi way traffic lights at Leiston level crossing, Abbey Road 17-27 November for enabling works to the level crossing.
Multi way traffic lights at Leiston level crossing, Abbey Road 1 - 19 December to install the UKPN DNO supply for the level crossing and rail route.
Speed restrictions
A12 between Glemham and Benhall, 30 mph speed limit in place whilst works are carried out to construct the new by-pass.
A12 Friday Street 30 mph speed limit in place whilst works are carried out to construct the new roundabout.
A12 between Kelsale and Yoxford, 30 mph speed limit in place whilst works are carried out to construct the Sizewell Link Road and roundabout.
A12 Darsham, 30 mph speed limit in place whilst works are carried out to construct the Northern Park & Ride roundabout.
B1122, Lover’s Lane and Sizewell Gap 30 mph speed limit in place.
B1125, 30mph and 50mph speed limits in place associated with speed cameras.
Buckleswood Road and Westward Ho 30 mph speed limit in place whilst works are carried out to construct the Green Rail Route.
30 mph speed restrictions on Eastbridge Road.
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