Bridge Strike Awareness
A practical HGV driver awareness course covering vehicle dimensions, route planning, low-bridge signs, arch bridges, load and trailer changes, safe decision-making and immediate incident reporting.
1. Bridge Strike Awareness
A bridge strike is a collision involving a vehicle, its load or its equipment and a bridge or other overhead structure.
Bridge strikes can endanger road users and rail passengers, damage infrastructure, disrupt services and expose both drivers and operators to enforcement or regulatory action.
The basic prevention principle is simple: know the vehicle, know the route and obey the signs.
- Treat bridge-strike prevention as a core road-safety responsibility.
- Never assume that a familiar route is suitable for every vehicle or trailer combination.
- If there is doubt about clearance, stop before the restriction and resolve the doubt.
2. Know Your Vehicle Dimensions
Before starting a journey, establish the maximum travelling height and width of the complete vehicle, including the trailer, load and any equipment.
For vehicles over 3 metres high, the correct maximum height must be displayed in the cab.
Vehicle height can change when a different trailer is coupled, the fifth-wheel position changes, a load is added or removed, or equipment is carried above the normal body height.
- Measure when necessary; do not guess.
- Do not rely only on a trailer headboard or an old height figure.
- Check the in-cab height indicator after a vehicle, trailer or load change.
3. Route Planning
Routes should be planned in advance so far as reasonably practicable, taking account of the vehicle's dimensions and any low bridges or restricted structures.
Use navigation designed for large goods vehicles and enter the correct vehicle dimensions. A car sat-nav may route a commercial vehicle towards unsuitable roads or low bridges.
A diversion, road closure or last-minute route change must be treated as a new route-planning decision.
- Check the route against the actual vehicle being driven.
- Avoid shortcuts that have not been checked for height and width restrictions.
- If diverted onto an unfamiliar road, slow down and reassess the route before continuing.
4. Low Bridge Signs
Low bridges are normally signed where the available clearance is below the signing threshold. Drivers must identify the displayed height restriction before committing the vehicle to the bridge.
A red circular height restriction is a mandatory prohibition. An overheight vehicle must not pass it.
Triangular signs warn of restricted headroom. Some high-risk bridges also use vehicle detection and flashing variable-message warnings.
- Read both metric and imperial values where displayed.
- Never 'try the bridge' because the vehicle appears close to the stated clearance.
- If the vehicle exceeds or may exceed the available clearance, stop and use an alternative route.
5. Arch Bridges
At an arch bridge, the available height normally reduces towards the sides of the arch. Road markings and goal-post style markings may show the area in which the signed clearance applies.
A vehicle that is both high and wide needs extra care because the maximum usable height may be lower away from the centre of the arch.
Only position towards the centre when it is safe and lawful to do so, with full awareness of oncoming traffic and other road users.
- Approach slowly and read all bridge markings.
- Keep the vehicle within the marked safe area where provided.
- Do not assume a signed height applies across the full width of an arch.
6. Loads, Trailers & Equipment
Bridge-strike risk must consider the complete travelling profile, not just the tractor unit or empty trailer.
Loaded trailers, machinery, containers, double-deck bodies, lifting equipment, cranes, raised equipment and changes in coupling geometry can all affect travelling height.
The driver should confirm that anything capable of being raised or deployed is in its correct travelling position before moving.
- Re-check height after changing trailer or load.
- Include equipment and load in the overall height calculation.
- Report any mismatch between measured height and displayed vehicle information.
7. What To Do If Clearance Is Doubtful
If a route is obstructed by a bridge that is lower than the vehicle, or if the driver is unsure of the available clearance, the safe action is to stop before the restriction.
Do not rely on visual judgement from the cab. Seek a safe alternative route or obtain competent advice.
Do not reverse or turn in a dangerous location. Manage the situation without creating a second road-safety risk.
- Stop before committing the vehicle to the bridge.
- Use a safe place to reassess the route.
- Never continue simply because another large vehicle has passed underneath.
8. If A Bridge Strike Happens
A railway bridge strike must be reported immediately so the railway authority can protect rail traffic and arrange an inspection.
Use the telephone number on the bridge identification plate where one is provided. If there is no usable plate, contact the police using 999. Network Rail also publishes its emergency helpline as a last-resort reporting route.
Inform the employer, keep people away from danger, follow emergency-service or infrastructure-controller instructions, and do not move the vehicle if doing so could increase the risk.
- Do not wait until returning to the depot to report a strike.
- Give the bridge location/ID, vehicle details and a clear description of what happened.
- Treat every bridge strike as a serious safety incident.
Bridge Strike Awareness Assessment
30 questions • one answer per question • 90% pass mark (27/30). Questions are shuffled on each new attempt.