Loading Dock Safety: Preventing Trailer Creep

Loading dock safety: three main accident scenarios

The loading dock is the shortest but busiest point in a warehouse: in the same few square metres, a forklift, a pallet truck, pedestrian workers, a lorry driver and a vehicle that may move all come together. Loading dock safety is therefore achieved not with a single piece of equipment but through communication between the vehicle, the dock and people.

Most serious accidents at the dock come down to three scenarios:

Scenario	How does it happen?	Main measure
Early departure of the lorry	The driver thinks loading is finished or takes a signal from the wrong dock; the vehicle leaves the dock while the forklift is inside the trailer	Key handover or vehicle restraint, signal light, a written "all clear" rule
Trailer creep	The pushing and braking forces created each time the forklift enters and leaves the trailer slowly move it away from the dock; the gap grows	Wheel chocks, vehicle restraint, parking brake applied
Forklift falling	A gap has opened, the dock leveller has come out of position, or the door of an empty dock has been left open	Correct position of the dock leveller, door and barrier at empty docks, edge markings

Art. 43 of Annex 1 of the Regulation on Health and Safety Measures in Workplace Buildings and Annexes requires loading bays and ramps to be suitable for the dimensions of the loads to be carried, to be safe in a way that prevents workers from falling and to have at least one exit point; loading bays exceeding a certain width need an exit at each end where technically possible. Art. 36 of the same annex also requires all routes, including loading bays and ramps, to be suitable for the safe movement of pedestrians and vehicles, and the floor to be free of unevenness, holes and slipperiness.

Early departure of the lorry: who gives the "all clear"?

What early departure accidents have in common is a gap in communication. While waiting in the cab, the driver misinterprets noises at the dock, a horn or a hand signal, or thinks a signal meant for the vehicle at the neighbouring dock was given to them. The decision "loading is finished, you can go" therefore needs to be given by a single person using a single method.

Three methods used in practice give the safest result when used together:

Key handover: Once the vehicle has backed onto the dock, the driver hands the ignition key to the dock supervisor and waits in the rest area. The key is returned after loading is finished and the door is closed.
Signal light: A light outside the dock door, visible to the driver, means "red: do not approach, do not move" and "green: you may move"; a light inside also shows the forklift operator whether the vehicle is secured.
Vehicle restraint: A mechanical lock engaging the trailer's rear bumper or a wheel physically prevents the vehicle from leaving until it is released, and works in conjunction with the signal light.

Whichever is chosen, the rule should be written down and explained to arriving drivers at the entrance gate. A short, illustrated information card is useful for drivers of foreign-registered vehicles or those arriving for the first time.

Trailer creep and wheel chocks

Trailer creep happens without being noticed. With every forklift entry, braking and acceleration push the trailer a few centimetres; by the end of loading, the lip of the dock leveller may have reached the very edge of the trailer floor. On the next entry the leveller slips off the trailer and the forklift falls into the gap.

Wheel chocks reduce this risk in a cheap and simple way:

The chock is placed in front of the wheels of the axle closest to the dock, in the direction of vehicle travel. Placing chocks on both sides is safer.
The chock should be suitably sized for the vehicle and the ground, sturdy and non-slip; chaining it to the dock prevents it from going missing.
Who places and who removes the chock is written down; it is not removed before the signal light turns green.
On icy or wet ground the chock can slip; floor cleaning and anti-icing measures are planned together in winter.

Trailers detached from the tractor unit (lowered onto their landing legs) carry a separate risk: the trailer's front landing legs may not be able to bear the load, or may sink into the ground, when the forklift enters the front section of the trailer. In this case an additional support stand is placed at the front of the trailer and it is checked that the legs are resting on firm ground.

The dock leveller: maintenance and use

A dock leveller is a hydraulic or mechanical platform that bridges the height difference and gap between the dock and the trailer floor. Used correctly, it makes forklift passage safe; used incorrectly, it becomes the source of an accident.

Capacity: The leveller's rated capacity is written on its plate; the total weight of the forklift and load must not exceed it.
Lip overlap: The lip at the end of the leveller must rest on the trailer floor by a sufficient amount. A lip barely touching the edge will slip under the first load.
Gradient: If the height difference between the dock and the trailer exceeds the gradient the leveller allows, it is not suitable for the forklift and load; the vehicle is moved to another dock.
Stored position: When there is no vehicle, the leveller is left closed and level with the floor, and the dock door is closed.
Crush points: Feet can be trapped in the side gaps of the leveller and at the lip hinge; side skirt plates and yellow-black marking are used.
Maintenance: Hydraulic leaks, broken hinges and deformed lips are checked regularly; maintenance is carried out according to the manufacturer's instructions and recorded.

Dock doors should not be forgotten either. Under Annex III of the Work Equipment Regulation, industrial doors are subject to periodic inspection at least once a year unless a shorter period is specified in the standard; the same maximum period applies to forklifts and pallet trucks.

Forklifts falling from the dock and working inside the trailer

A forklift falling from the dock happens in two ways: falling through a dock door left open when there is no vehicle, and trying to cross the gap opened between the vehicle and the dock. The second scenario is prevented by the chock and restraint measures above; the first by the organisation of the dock:

At a dock with no vehicle, the door is kept closed; if the door is to stay open, an easily visible barrier is placed at the dock edge.
Dock edges are marked with yellow-black tape; a wheel stop at the edge also limits how close the forklift can get.
When working inside the trailer, the soundness of the trailer floor is checked; a rotten or holed floor can trap the forklift's wheel.
If the inside of the trailer is dark, a dock light is used; forklift headlights alone are not enough.
Before entering the trailer, the forklift operator checks that the signal light is red, i.e. that the vehicle is secured.

Pedestrian movement in front of the dock is also a risk in this area. Drivers should not get out of the vehicle and walk in front of the dock; waiting should take place in a designated rest area. For separating pedestrians and forklifts inside the warehouse, see our article on the forklift and pedestrian traffic plan in the warehouse.

Daily checklist for the dock

At the start of each shift, the dock supervisor checks the following items:

Are the signal lights working inside and outside?
Are the chocks in place, sound and chained?
If there is a vehicle restraint, has it been tested?
Are the dock levellers closed and level with the floor, and is there any hydraulic leak?
Are the doors of empty docks closed or fitted with a barrier?
Are the dock apron and interior clean, dry and free of ice?
Is the lighting of the dock and the trailer interior sufficient?
Is the driver waiting area designated and being used?
Have the daily checks of the forklifts been carried out?

For the forklift operator's own checks see our article on the forklift operator's daily check, and for operator certificate requirements see our article on the forklift operator certificate.

At warehouse and dispatch areas in Bursa and the surrounding provinces, including logistics businesses linked to the port and free zone in Gemlik, Bursa Sistemer incorporates dock arrangements into the risk assessment as part of its OHS specialist service. Other risks in the sector are on our logistics and warehousing page, and regional information is on our Gemlik page. You can track periodic inspection dates with the OHS calendar tool.

Frequently Asked Questions

Is a wheel chock enough on its own?

A chock reduces trailer creep, but it does not always prevent the driver from moving the vehicle. The safest arrangement is to use the chock together with key handover or a vehicle restraint and a signal light.

Is a dock leveller subject to periodic inspection?

The dock leveller is maintained according to the manufacturer's instructions and the maintenance is recorded. Industrial doors such as dock doors, as well as forklifts and pallet trucks, are subject to periodic inspection at least once a year under Annex III.

Can the driver wait in the vehicle during loading?

The business decides where drivers wait. The safest practice is for the driver to hand over the key and wait in a designated rest area away from the front of the dock.

Can a forklift enter a trailer resting on its landing legs?

It can, but it must be checked that the trailer's front landing legs are resting on firm ground and, if necessary, an additional support stand must be placed at the front. Otherwise the trailer can tip forwards.