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.
What should sites in Renfrewshire and Inverclyde consider?
Sites around Renfrewshire and Inverclyde that run night shifts often find traffic lights easier for drivers to read than staff waving or knocking on the cab door. If a site in Renfrewshire and Inverclyde has had door panels damaged by levellers raised too early, a leveller-to-door interlock is a straightforward fix to consider.
Whether your unit in Renfrewshire and Inverclyde has one dock or twenty, the survey looks at each bay's existing controls before we quote a fixed price in writing.
Here is what happens after you contact us about a site in Renfrewshire and Inverclyde. 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.
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.
What happens on site when traffic lights and interlocks are fitted?
Fitting lights and interlocks is mainly electrical work, and each bay is out of use while its controls are connected and tested. Working bay by bay keeps the rest of the dock running.
- Fix the signals: the outside light is mounted on brackets at a height drivers can see, and the inside light beside the door.
- Run the cables: wiring is run in conduit or trunking between lights, sensors and control panels.
- Isolate and connect: the door and leveller supplies are isolated and locked off while the interlock wiring is connected, or a new bay panel is fitted.
- Test every sequence: each interlock is tested, including what happens if a step is attempted out of order.
- Brief staff: dock staff are shown the new sequence, and signs are fitted for drivers.
It helps if you can provide any electrical drawings for the dock, access to the distribution board, a person who can authorise isolations and an agreed order for releasing bays.
Towns we cover in Renfrewshire and Inverclyde
Choose a town below to see how we handle dock traffic lights and interlocks in that part of Renfrewshire and Inverclyde.
Budget range for supply and fit. The written quote after a free survey is the fixed price. All guide prices.
What do the rules in Scotland mean for the work?
HSE is the workplace safety regulator in Scotland. At a loading bay in Renfrewshire and Inverclyde, doors need to satisfy regulation 18 of the Workplace (Health, Safety and Welfare) Regulations 1992, dock equipment must be kept safe under PUWER, and drivers must be prevented from pulling away too early. We check what applies at survey.
Questions
What warranty comes with new loading bay equipment?
New equipment comes with the manufacturer's warranty, which varies by product. Our workmanship terms are set out in writing in the quote for your Renfrewshire and Inverclyde site, so you can see what is covered before you commit. Check the warranty terms for any servicing conditions, and we can quote for planned maintenance once the installation is complete.
Can you work alongside our main contractor on a new build in Renfrewshire and Inverclyde?
Yes. For new warehouses and fit-outs, we can supply and install the dock package as part of a wider project, working to the main contractor's programme, site rules and permits. We will need drawings, dock levels and the programme, and we coordinate pit details, power supplies and door openings with the relevant trades before installation begins.
Do traffic lights and interlocks need maintenance?
Yes. Lights, sensors and interlocks should be checked at each planned service visit, including testing the full sequence and confirming that steps attempted out of order are blocked. As part of the dock equipment they fall under PUWER, which requires work equipment to be maintained in a safe condition.
Which way round do the inside and outside lights work?
The inside and outside lights always show opposite colours. While a trailer is being loaded, the outside light is red so the driver stays put and the inside light is green so staff can work. When loading is finished and the door is closed, the inside light turns red and the outside light turns green for the driver.
Other services in Renfrewshire and Inverclyde
Full guide to dock traffic lights and interlocks · All loading bay services in Renfrewshire and Inverclyde

