Traffic on the M5 will face delays of 60 to 90 minutes on several days as three oversized silos are transported north from Avonmouth Docks. The convoys move under police escort at speeds of 20 to 25mph, significantly slower than usual motorway traffic.
Slow convoys under police escort
Abnormal loads are vehicles or freight exceeding standard legal size or weight limits, requiring special planning and permission before travelling on motorways. In this case, three large silos are being carried from Avonmouth Docks towards Walsall.
The size of the loads means the route is carefully planned and police provide an escort to manage other road users. The convoy’s pace is around 20 to 25mph, which is far below typical motorway speeds.
Traffic held behind convoys
Although the M5 will remain open during the movements, vehicles must slow down behind the convoys. This narrowing of speed creates queues as faster traffic catches up with the slow-moving loads.
National Highways warns motorists to expect delays of up to 90 minutes. Drivers should consider journey timing carefully if travelling through the affected stretch of the M5 during the scheduled movements.
Planned movement, not an incident
Unlike collisions or unplanned closures, these abnormal load transfers are scheduled in advance. The route and timings are coordinated to minimise disruption. Nonetheless, the physical challenge of moving extremely large equipment on a busy motorway remains significant.
Why motorway capacity changes
An abnormal load reduces motorway capacity sharply. A section that usually handles traffic at 70mph must accommodate vehicles moving at a quarter of that speed. This creates a bottleneck, slowing all following traffic.
Similar effects have been seen during recent M60 disruptions, though those stemmed from incidents rather than planned movements. Here the slow pace is expected and controlled, helping manage traffic flow.
Practical advice for drivers
Drivers should allow extra time if travelling on the M5 during these transfers. National Highways’ advance warning offers the chance to plan journeys outside the affected periods and avoid unnecessary delays.
The wider infrastructure challenge
The strategic road network must support more than cars and standard freight. Exceptional loads like these silos are vital for industry but require compromises in traffic flow to move safely.
Such movements inevitably reduce speed and capacity on busy motorways temporarily. For drivers behind the convoy, this means slower journeys. For highways and freight operators, it highlights the ongoing challenge of integrating abnormal load transfers into a heavily used road network.
