Must a heavy lorry display parking lights when parked on a Northern Ireland road at night?

Yes. Northern Ireland Highway Code rules require parking lights for vehicles left on roads where lighting exemptions do not apply; heavy lorries cannot rely on the normal small-vehicle exemption.

Rules 249 and 250 distinguish vehicles and road speed limits. Vehicles parked on roads with limits above 30 mph must show parking lights; the limited lights-off concession on roads at 30 mph or below is for specified smaller vehicles in particular positions. A large goods vehicle does not automatically qualify for that concession. Check the vehicle category, whether it is parked in a recognised space and any projecting load before leaving it at night. Vehicle conspicuity is critical on unlit roads.