Must admit I considered the approach of using trig from the comfort of the cab, but you'd have to be able to see the peak of the uneven load from two adjacent sides (peaks occurring toward the middle of the container and which only modestly exceed the height of the container, may not be visible on two adjacent sides at any reasonable distance), the peak would have to be occluded by the container at not-too-close an angle (i.e. if the peak is near to the edge of the container and clearly exceeds the height of the container even at close range, so that it is only occluded at an angle close to 90 degrees, then it would have to be measured directly to avoid an excessive margin of error), and you'd have to take all observations on a completely level area (because you have no tools capable of correcting for uneven ground), and the top of the container itself would still have to measured and would have to be completely level around its perimeter relative to the ground (or be measured at all the points where it coincides with the lines of observation). Another point the load can make a difference, I took a low Euroliner through a particularly very low bridge years ago in Sheffield once, it was mm.s clearance, I watched it through with head and shoulders out of window and just got it under. Details of how to obtain a copy of the Road Vehicles (Constructionand Use) Regulations 1986 SI 1986 No. 1078 can be found below. For information on the additional lighting requirements for wide loads in the hours of darkness or poor visibility, please refer to the DfT information sheet on this subject. 3. Extract from the Road Vehicles (Construction and Use) Regulations 1986 – Schedule 12 If you feel the need to measure various trailers, generally speaking here, all you need to know is the running and low setting heights, for low bridge clearance. Two clear working days notice to Police ( C&U schedule 12, para 4), Attendant required ( C&U Schedule 12, para 2), Marker boards front and rear ( C&U Schedule 12, para 3), Additional lights required during hours of darkness or poor visibility.

Due to the height of most road bridges a vehicle and its load should not exceed a height of 5.03m. This is the normal maximum clearance under highway bridges in the UK.

HGV height indicators

f) every marker fitted in accordance with this paragraph shall be kept clean and unobscured and between sunset and sunrise be illuminated by a lamp which renders it readily visible from a reasonable distance and which is so shielded that its light, except as reflected from the marker, is not visible to other persons using the road. Road vehicles are generally less than 4.5m tall however there are instances where vehicle height exceeds this, notably when a tipper is raised or when a load protrudes above the top line of the vehicle. A driver should always know their HGV height (including load) and must remain vigilant about any changes to the height which can vary significantly depending on the load being carried. Vehicle height can change each time a vehicle is loaded, unloaded and reloaded. v) each marker is clearly visible within a reasonable distance to a person using the road on that side of the projection;

Follow all local regulations and guidelines for measuring the height of HGV vehicles, including any specific procedures or safety protocols. Chief Officer of Police” has, in relation to England and Wales, the same meaning as in the Police Act 1964, and in relation to Scotland, the same meaning as in the Police (Scotland) Act 1967, ‘working day’ means a day which is not a Sunday, a bank holiday, Christmas Day or Good Friday, and ‘bank holiday’ means a day which is a bank holiday by or under the Banking and Finance Dealings Act 1971, either generally or in the locality in which the road is situated. 2. Attendants The table below is a summary of the requirements applicable to loads overhanging the sides of a vehicle as set out in regulation 82 of C&U. Load projection or overall width Regulation 100 (2) of the Road Vehicles (Construction and Use) Regulations 1986 (as amended), requires all vehicles to not be used or loaded in such a way that they endanger either those using the vehicle or other road users. Further information on the safety of loads can be found in DfT’s information sheet on the Safety of loads. 7. Legal information So, to help you do these we've updated our guidance and published a new video, showing you what you need to do.

HGV height changes

But how can bridge strikes be avoided? Simply put, the easiest way to avoid bridge strikes is to ensure that a driver is made aware of and is constantly reminded of the height of their HGV. The standard minimum clearance over every part of the carriageway of a public road is 16 feet 6 inches (5.03 metres). When the clearance over any part is less than this, standard warning signs both on and prior to the structure should be provided. The stated clearance should be at least 75mm less than the measured height. ii) when another motor vehicle is used for the purpose of assisting in their propulsion on the road, the person or persons employed in driving that other motor vehicle shall not be treated as a person or persons employed in attending to the first mentioned vehicle or any vehicle or vehicles drawn thereby. 3. Marking of longer projections Where the height variation is <150mm cab notices can be standardised at the overall height of the highest vehicle/trailer combination (i.e. where no combination will be greater than 150mm lower than the indicated height iv) it, and any means by which it is fitted to the projection, impedes the view of the driver as little as possible, and