Visibility failures kill quietly: the low sun through a filthy screen, the misted window on a wet morning, the mirror cracked since Tuesday. The Highway Code’s vehicle maintenance annex turns that into hard rules - and several of them carry the MUST that signals a legal requirement, not advice. For professional drivers and their operators, visibility items are also among the easiest defects for any examiner to spot, which makes them the least defensible to find.
The annex is direct: windscreens and windows MUST be kept clean and free from obstructions to vision. Two duties in one rule - cleanliness and obstruction. The cracked phone mount, the sat-nav parked in the swept area, the air freshener forest, the clipboard wedged at the screen base: all obstructions, all common, all citable. Lights, indicators, reflectors and number plates MUST be kept clean and clear as well - the winter road film that coats the rear of a trailer in twenty minutes is exactly what this rule exists for. And lights MUST be properly adjusted to prevent dazzling other road users - aim is part of the legal state of the lights, not an MOT-only concern.
Window tinting has its own hard limit: you MUST NOT use a vehicle with excessively dark tinting applied to the windscreen or to the glass in any front window to either side of the driver. Factory tinting complies with the Visual Light Transmittance standards; it is the aftermarket film that gets vehicles into trouble. There are no VLT limits for rear windscreens or rear passenger windows - but the front glass is a hard boundary.
The visibility rules sit inside a broader daily duty that the annex frames as special care: lights, brakes, steering, exhaust system, seat belts, demisters, wipers, washers and any audible warning systems all working. Note demisters, wipers and washers making the list alongside brakes and steering - a driver who cannot clear the screen is as blind as one whose brakes have failed, and the Code treats the systems with matching seriousness.
The annex adds the dashboard discipline: warning lights illuminate at ignition and should go out when the engine starts - if they do not, or if they come on while driving, stop and investigate, because you could have a serious fault. A charge warning light on the move may mean the battery is not charging, heading for loss of power to lights and electrical systems. And it sets the weekly rhythm: check tyre pressures weekly, before the journey, when tyres are cold; check fluid levels at least weekly - low brake fluid may result in brake failure and a crash.
Visibility is not only about the vehicle. The same annex requires the driver to ensure the seat, seat belt, head restraint and mirrors are adjusted correctly before driving - a rule with special force in multi-driver fleets where the cab changes hands every shift. Mirrors adjusted for the previous driver are mirrors adjusted for nobody. The ten seconds of seat-and-mirror discipline at shift start is part of the legal state of the vehicle, not a comfort preference.
Visibility defects are the gifts of roadside enforcement: a cracked screen in the wiper sweep, a dead number plate lamp, an overloaded dashboard shrine - all visible from outside the vehicle without a torch. They convert an otherwise clean stop into a recorded defect, and in the annual test they live in the visibility category that DVSA’s class 7 data shows failing around seven per cent of vans. The fix costs nothing but habit: the walkaround check that includes glass, washers, wipers, mirrors and lamps - done by a driver who knows these are MUSTs, not suggestions.
Clean glass, clear obstructions, working wipers and washers, demisters that clear, lamps clean and correctly aimed, mirrors set for the driver in the seat. Every one is a legal requirement stated in the Highway Code’s maintenance annex, every one is visible to any examiner, and every one is within the driver’s daily power. Visibility is the cheapest compliance there is - and the most embarrassing to fail.
For operators, the driver’s daily duties become a management obligation: the walkaround check has to cover visibility items explicitly, the defect reporting route has to make a worn wiper as reportable as a worn brake, and the rectification culture has to treat screen damage in the swept area as a do-not-drive defect rather than a next-service item. The fleets that fail visibility items at annual test are rarely the ones with bad vehicles; they are the ones whose daily check was a signature exercise. A visibility checklist the driver can complete in two minutes - glass, mirrors, lamps, wipers, washers, demister - closes the gap between the Code’s MUSTs and Monday morning.