A severe heavy goods vehicle collision on the M4 in Wiltshire closed the westbound carriageway between Junction 16 near Swindon and Junction 17 near Chippenham early Thursday morning, according to National Highways.
Emergency services responded to the incident around 2:11 a.m. after a westbound HGV struck the central reservation. The impact caused extensive damage to approximately 300 meters of the central barrier and left the vehicle resting inside the barrier structure, forcing the closure of lane three on the eastbound carriageway as well.
Major Diesel Spillage and Traffic Disruption
The crash resulted in a major diesel spillage extending across at least 100 meters of the westbound lanes. Trapped traffic rapidly backed up over a mile behind the scene, leaving some motorists stranded for hours as recovery teams and emergency personnel arrived.
Wiltshire Police are leading the operational response, supported by National Highways Traffic Officers, who began turning affected traffic around from the rear of the queue. Due to the severe structural damage and environmental contamination, National Highways warned that the westbound carriageway would likely remain closed well into the morning peak travel period.
Official Diversion Routes Put in Place
Drivers caught in the disruption or planning journeys through the area are advised to follow the Solid Diamond diversion symbols displayed on local road signs. National Highways has provided distinct routes based on vehicle height constraints:
- Vehicles under 4.2m: Exit the M4 westbound at J16, keep left at the slip road, and take the A3102 towards Royal Wootton Bassett. Continue onto the B4042 toward Brinkworth to reach the Priory Roundabout with the A429, then join the A429 to re-enter the motorway at J17.
- Vehicles 4.2m and taller: Exit at J16, take the A3102 past Royal Wootton Bassett, Church End, and Hilmarton toward Calne. Proceed onto the A4 to the Chequers Roundabout in Chippenham, then take the A350 northbound to join the M4 at J17.
Travel Advice and Contact Information
Motorists are strongly encouraged to allow extra time for their journeys, plan ahead, or delay travel if passing through Wiltshire. Real-time travel updates remain accessible via National Highways’ regional social media channels, or by calling their 24/7 contact center team on 0300 123 5000.
