Ask the MAC

Q) We have got flashing light beacons fitted to the rear of our vehicles, however, when they are parked on a gradient you cannot see the beacons from the front of the vehicle, is this OK?

A) Schedule 16 of the Road Vehicles Lighting Regulations 1989 states that every warning beacon “shall be so mounted on the vehicle that the centre of the lamp is at a height not less than 1200mm above the ground”. With regards to angles of visibility, the light shown from at least one beacon (but not necessarily the same beacon) “shall be visible from any point at a reasonable distance from the vehicle or any trailer being drawn by it”. As the distance is not specified, we don’t have any guidelines as to how far from the vehicle the beacon has to be visible from. In section 05 (General Vehicle Issues) (05.3 roof mounted beacons) of Part two of the Chapter 8 traffic signs manual, it states that “if the main roof-mounted beacon is likely to be obscured from the rear by parts of the vehicle or any equipment carried on the vehicle, additional beacons should be fitted toward the rear of the vehicle where they will remain visible”. If we look at this from the other way round and the beacon is fitted at the rear but cannot be seen from the front, then an additional beacon fitted to the front of the vehicle should be considered, or another thought would be to put the existing beacon on a riser.

Q) We have noticed an increase in drivers that are leaving their engine running in the hot weather in order to keep the air conditioning working and to keep the cabs cool whilst they are on break. As a transport manager I have the pressure of ensuring our operation works towards net zero but I’m also responsible for the wellbeing of my staff. Can you tell me if there’s an industry standard on this subject?

A) With regards to leaving an unattended vehicle with the engine running, this is covered within the Highway Code Rule 123, and the Road Vehicles (Construction & Use) Regulations 1986 (C&U regulations) 98, and 107.

Highway Code Rule 123 states that you must not leave a parked vehicle unattended with the engine running, or leave a vehicle engine running unnecessarily, while that vehicle is stationary on a public road.

C&U regulation 98 (Stopping of engine when stationary) states the driver of a vehicle shall, when the vehicle is stationary, “stop the action of any machinery attached to or forming part of the vehicle so far as may be necessary for the prevention of noise”. However, this does not apply to:

• When the vehicle is stationary owing to the necessities of traffic.
• So as to prevent the examination or working of the machinery where the examination is necessitated by any failure or derangement of the machinery or where the machinery is required to be worked for a purpose other than driving the vehicle or
• In respect of a vehicle propelled by gas produced in plant carried on the vehicle, to such plant.

C&U regulation 107 (Leaving motor vehicles unattended) states that “no person shall leave, or cause or permit to be left, on a road a motor vehicle which is not attended by a person licensed to drive it unless the engine is stopped and any parking brake with which the vehicle is required to be equipped is effectively set”.

Published On: 17/07/2025 15:00:00