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 Hertfordshire?
If a site in Hertfordshire 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 Hertfordshire with inflatable shelters often add interlocks so the shelter only inflates once a trailer is docked and restrained.
Sites around Hertfordshire that run night shifts often find traffic lights easier for drivers to read than staff waving or knocking on the cab door.
A single contact at Loading Bay Doors handles your project in Hertfordshire from start to finish. The free site survey and fixed written quote come first, with no obligation to proceed. We then book the installation for times that suit the operation, including out of hours by arrangement, and manage the specialist engineers on site. At the end we commission and test the equipment, walk your team through it and provide the documentation.
What does HSE guidance say about stopping drivers leaving too early?
HSE guidance (followed by HSENI in Northern Ireland) says there should be safeguards against drivers driving away from a loading bay too early, and it names traffic lights as one of the measures. Vehicle or trailer restraints, and the person in charge keeping keys or paperwork until it is safe, are the others listed in HSE's guide to workplace transport safety (HSG136) and its loading factsheet.
Traffic lights are a signal, not a physical barrier, so they work best as part of a clear procedure or alongside a restraint. Your risk assessment should decide the combination. In Northern Ireland the regulator is HSENI.
Interlocks also touch on door safety law. Under regulation 18 of the Workplace (Health, Safety and Welfare) Regulations 1992, or the Northern Ireland 1993 equivalent, powered doors need suitable and effective features to prevent them trapping anyone. Interlocks must never bypass those features, and door control work should respect BS EN 12453, the standard for safety in use of power-operated doors.
Read more in our guide to preventing drive-away and trailer creep.
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.
Towns we cover in Hertfordshire
Choose a town below to see how we handle dock traffic lights and interlocks in that part of Hertfordshire.
- Watford
- Hemel Hempstead
- Stevenage
- St Albans
- Welwyn Garden City
- Cheshunt
- Hatfield
- Bishop's Stortford
- Borehamwood
- Hitchin
- Hoddesdon
- Letchworth Garden City
- Harpenden
- Bushey
- Hertford
- Rickmansworth
- Potters Bar
- Berkhamsted
- Ware
- Royston
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 England mean for the work?
Workplace safety in England is regulated by HSE. For a loading bay in Hertfordshire, that means doors meeting regulation 18 of the Workplace (Health, Safety and Welfare) Regulations 1992, equipment maintained under PUWER and suitable safeguards against vehicles driving away too early. We check what applies at survey and design the bay accordingly.
Questions
How do you price dock traffic lights and interlocks for a site in Hertfordshire?
Guide budgets for supply and fit are £650 to £3,400 per bay, excluding VAT. The figure moves with size, insulation, the operator, electrics, access, any pit or groundworks and out-of-hours working. Where levellers are involved, the guide assumes an existing, sound pit. After the free survey you receive a fixed written quote, and that is the price for the agreed scope.
Can you work outside our normal operating hours in Hertfordshire?
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.
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.
Other services in Hertfordshire
Full guide to dock traffic lights and interlocks · All loading bay services in Hertfordshire