Coupling & uncoupling
What's the problem?
Accidents and dangerous situations occur all too often when drivers of large goods vehicles (LGVs) fail to follow safe coupling and parking procedures. Unsafe practices often lead to vehicle runaway or trailer rollaway situations. They can result in serious and fatal injury to the driver or others, and costly damage to both vehicles and property.
Guidance
A risk assessment should be made of each type of vehicle the driver will use to decide if one of the generic procedures provided below can be used or if it must be adapted to suit a specific situation.
The driver should be trained in the safe system of work and simple monitoring systems should be set up to check that safe systems are followed at all times - a careless driver can be a danger to others as well as themselves.
Before parking hauliers and site operators should ensure that the area is level and firm enough to support both the trailer landing legs. Additional lighting may be necessary if operations are being carried out during hours of darkness to make sure the procedure is carried out safely and to reduce other risks such as falling from the vehicle.
Coupling procedure for standard semi - trailers (where there is room to operate safely between the rear of the tractor cab and the front of the semi trailer)
- Slowly reverse the tractor unit in a straight line towards the front of the trailer.
- Apply the tractor unit parking brake, stop the engine and remove the keys.
- Check the trailer parking brake is applied.
- Make any necessary adjustments to the trailer coupling height and slowly reverse the tractor unit under the trailer until the 5th wheel jaws engage.
- Apply the tractor unit parking brake, stop the engine and remove the keys.
- Carry out a visual check that the 5th wheel jaws have engaged correctly and fit the security "dog clip" or other safety device.
- Carry out a second test that the 5th wheel jaws have engaged by selecting a low forward gear and with the trailer brakes still applied slowly pulling forward.
- Apply the tractor unit parking brake, stop the engine and remove the keys.
- Connect the service airline (yellow) and electrical connections.
- Connect the emergency airline (red) and watch for any unexpected movement. (If the trailer moves, immediately disconnect the emergency airline (red) and check that the trailer parking brake has been applied.
- Wind up the landing legs and secure the handle.
- Fit the number plates and check that the lights work.
- Carry out visual and functional vehicle checks, and release the trailer handbrake before setting off.
Uncoupling procedure for standard semi trailers (where there is room to operate safely between the rear of the tractor cab and the front of the semi trailer)
- Park the combination in a straight line.
- Apply the tractor unit parking brake, stop the engine and remove the keys.
- Apply the trailer parking brake.
- Remove and stow the trailer number plate and lower the landing legs.
- Disconnect all of the air and electrical services and stow safely.
- Remove the security "dog clip" and pull the release handle to disengage the 5th wheel jaws.
- Slowly draw the tractor unit away from the trailer. If the tractor unit has mechanical suspension stop when the trailer is clear of the fifth wheel.
- Apply the tractor unit parking brake, stop the engine and remove the keys.
- Before leaving the trailer, walk round it to check that it is in a safe condition.
For close coupled semi trailers alternative procedures will need to be followed, for example using the "split coupling" or "cranked coupling" method. A risk assessment will be needed to find a suitable method. In these cases it is essential that the drivers understand the potential dangers to themselves or others if they do not follow the safe system.
Equipment such as central axle draw bar trailers and turntable draw bar trailers will need their own coupling procedure.
Examples of safe systems of work for all these vehicles can be found in the booklet "Code of practice: Coupling or Uncoupling & Parking of Large Goods Vehicle Trailers" which was published by the Institute of Road Traffic Engineers (IRTE) and HSE in March 2006. It is aimed at managers, supervisors and trainers, but has practical advice for everyone who has responsibility for the safety of large goods vehicles and drivers. Free copies of the document are available from the SOE IRTE website.