Dock traffic lights are red and green signals mounted outside and inside a loading bay to tell the driver and dock staff when it is safe to move or load. Interlocks are control links that stop equipment operating out of sequence, for example preventing the door opening until the trailer is restrained, or the leveller operating until the door is fully open.
How does this suit sites in Gwynedd?
New warehouses in Gwynedd can have lights and interlocks wired in during the electrical fit-out, avoiding retrofit cabling and keeping every bay on one control standard. Older docks in Gwynedd with separate door and leveller controls can be brought into a proper sequence by adding interlocks that stop equipment working out of order.
If a site in Gwynedd has had door panels damaged by levellers raised too early, a leveller-to-door interlock is a straightforward fix to consider.
Here is what happens after you contact us about a site in Gwynedd. We arrange a free survey, measure up and send a fixed written quote. If you go ahead, we manage the whole job, including ordering, delivery and coordination with your site team. Specialist installation engineers working under our management do the fitting, at times built around your loading schedule, with out-of-hours work by arrangement. Testing and handover documents close the job.
Which interlocks should a loading bay have?
The most useful loading bay interlocks stop the door opening until the trailer is in place or restrained, and stop the leveller operating until the door is fully open. Beyond that, the right set depends on the equipment fitted and your risk assessment.
- Door to restraint: the door cannot open until the restraint is engaged or a trailer is detected.
- Leveller to door: the leveller cannot be raised until the door is fully open, which prevents the lip hitting door panels.
- Door to leveller: the door cannot close until the leveller is back in its parked position.
- Restraint release: the restraint only releases once the door is closed and the leveller parked.
- Shelter to trailer: an inflatable shelter only inflates when a trailer is docked.
On a bay without a restraint, a trailer presence sensor can take its place in the door logic, although it confirms a trailer is there rather than holding it. Combining interlocks with vehicle restraints gives the strongest protection against drive-away.
How do inside and outside dock traffic lights work together?
Inside and outside dock lights always show opposite colours: when the driver sees red, dock staff see green, and the other way round. Each light is aimed at a different person, so each one only ever gives one instruction.
- Outside light, facing the driver: red means stay on the bay because loading is in progress; green means the bay is clear to leave or to reverse on to.
- Inside light, facing dock staff: green means the trailer is in place and it is safe to open the door and load; red means do not open the door or enter the trailer.
Lights can be switched in three main ways:
- Manually, by a switch beside the door, relying on dock staff to change it at the right moment.
- By door position, so opening the door automatically turns the outside light red.
- By the restraint, so the light only changes when the trailer is physically held.
Towns we cover in Gwynedd
Each of the following towns in Gwynedd has its own page on dock traffic lights and interlocks, covering how we work and what to send us.
Budget range for supply and fit. The written quote after a free survey is the fixed price. All guide prices.
Which rules apply in Wales?
Sites in Gwynedd follow the rules for Wales. Forming a new opening or dock pit may need Building Regulations approval, and loading houses, canopies or new dock approaches can need planning permission from the local planning authority. We check what applies at survey, so any approvals are understood before the programme is fixed.
Questions
Will you deal with building control and planning for a project in Gwynedd?
We check at survey whether the work is likely to need approval. Forming a new opening or dock pit may need Building Regulations approval, a building warrant or building control approval, depending on the nation, and external structures such as loading houses can need planning permission. Where approval is needed, we explain what is involved, work with your designer or agent, and build it into the programme.
Can you work outside our normal operating hours in Gwynedd?
Yes, by arrangement. Evening, night and weekend working can be planned so the installation causes as little disruption as possible to your loading schedule. Out-of-hours work can affect the price, so mention it at the survey and we will include it in the written quote. The agreed times are confirmed in the programme before the job starts.
Can interlocks be fitted to a manual loading bay door?
Yes. A door position switch fitted to a manual door can confirm when it is fully open or fully closed. That signal lets the traffic lights change automatically and stops the leveller being raised until the door is out of the way.
Are dock traffic lights enough on their own to stop drive-away?
Traffic lights on their own are a signal, not a physical barrier, so they depend on drivers obeying them. HSE lists traffic lights among the measures against early drive-away, and many sites combine them with key or paperwork control or with a vehicle restraint. The right combination should come from your workplace transport risk assessment.
Other services in Gwynedd
Full guide to dock traffic lights and interlocks · All loading bay services in Gwynedd