- Location
- Johnstone, Renfrewshire and Inverclyde
- Main postcode district
- PA5
- Nearby (straight line)
- Paisley (3 miles), Barrhead (5 miles) and Erskine (6 miles)
- Survey and quote
- Free, with a fixed written quote
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.
Is this right for your site in Johnstone?
If a site in Johnstone has had door panels damaged by levellers raised too early, a leveller-to-door interlock is a straightforward fix to consider. Food and chilled operations around Johnstone with inflatable shelters often add interlocks so the shelter only inflates once a trailer is docked and restrained.
Whether your unit in Johnstone has one dock or twenty, the survey looks at each bay's existing controls before we quote a fixed price in writing.
We never ask you to commit before you have a fixed price. A free survey at your Johnstone site comes first, followed by a written quote. When the order goes ahead, we plan the installation around your operation, book any out-of-hours working you need and manage the specialist installation engineers on site. The job ends with a full test, a run-through for the people who will use the equipment and a set of handover documents.
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.
The same published guide range applies across Scotland; access, out-of-hours working and site conditions are confirmed at the free survey.
What do we check at the survey?
- Working hours, shift patterns and windows for out-of-hours work
- How drivers are prevented from pulling away too early
- Traffic routes for vehicles and separation of pedestrians
- Access for deliveries, cranes or lifting equipment during installation
- Age and condition of the equipment already in place
- Scope to convert ground-level doors into docks or add lift tables
Options to discuss
Door-linked lights
Lights that change automatically with the door position, using a door switch or a signal from the door control panel, so the outside light turns red as the door opens.
Full bay interlock panel
A single control panel that runs the door, leveller, restraint and shelter in the correct sequence, with indicators showing which step is active or blocked.
Regulations and approvals in Scotland
In Scotland, building work such as forming a new opening or a dock leveller pit may need a building warrant from the local authority before it starts. For sites in Johnstone, external structures such as loading houses or canopies may also need planning permission from the council. We check what applies at survey and factor any approvals into the programme.
Questions about dock traffic lights and interlocks in Johnstone
Will you deal with building control and planning for a project in Johnstone?
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.
What details do you need from us to quote for dock traffic lights and interlocks?
To get started, send the site address in Johnstone, the number of bays or openings, approximate sizes, and photos of the dock from inside and outside. Tell us what vehicles you load, what goods you handle and any temperature requirements. Drawings help on new builds. We then arrange the free survey and confirm the details before the written quote is issued.
Is the site survey in Johnstone free?
Yes. For new installations, replacements, upgrades, conversions and complete bays, the site survey and written quote are free and come with no obligation. The survey lets us measure the openings, check the dock and structure, and understand how the bay is used, so the quote reflects your site. Repair and servicing visits are different: they are chargeable, with the price agreed before anyone attends.
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.
Dock traffic lights and interlocks near Johnstone
Close neighbours of Johnstone with their own pages here: Paisley (3 miles), Barrhead (5 miles) and Erskine (6 miles). Choose one to see coverage details for that town.
Other loading bay services in Johnstone
Full guide to dock traffic lights and interlocks · Everything we do in Johnstone
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