When must I use headlights?

You must use headlights at night except on a road which has lit street lighting, and whenever visibility is seriously reduced. Highway Code rule 113, checked in 2026, states that duty and cites the Road Vehicles Lighting Regulations 1989, regulations 24 and 25. Night, the hours of darkness, is half an hour after sunset until half an hour before sunrise. Seriously reduced visibility is generally being unable to see for more than 100 metres, under rule 226.

Sidelights and the rear registration plate light are a different clock. They must be lit between sunset and sunrise, which is longer than the hours of darkness. That is how people end up on an unlit A-road at dusk with sidelights only: they treated sunset as the headlight trigger, then stayed on sidelights because the road felt familiar. On an unlit road after the hours of darkness begin, headlights are required. On a lit street-lit road that is generally a 30 mph road, or 20 mph in Wales, headlights at night are the exception in rule 113, not the duty.

Sunset to sunrise is the period for sidelights and the rear plate lamp. Hours of darkness, starting thirty minutes later and ending thirty minutes earlier, is the period for headlights on unlit roads. In December in Britain those thirty minutes are a large share of the commuting dark. In June they are easy to miss because the sky still looks light. The Lighting Regulations use those defined periods, not whether you personally found it gloomy.

Rule 115 still tells you to use dipped headlights in built-up areas at night and in dull daytime weather so you can be seen. That 'should' is not the same as the 'must' in rule 113, but it is the practical answer to 'the street lights are on, do I still dip?' Yes, in a built-up area, so other people can see you. Daytime running lights are not that answer. They often do not bring the rear lamps on, and they are not dipped beam.

Rule 114 says you must not use any lights in a way which would dazzle or cause discomfort to other road users, including pedestrians, cyclists and horse riders. That is a Lighting Regulations duty, regulation 27. Dip for oncoming traffic. Dip when you follow someone. Keep headlights dipped when overtaking until you are level with the other vehicle, then change to main beam if necessary, unless that would dazzle oncoming road users.

If oncoming headlights dazzle you, slow down and stop if you need to. Annex 6 says lights must be properly adjusted to prevent dazzling, and that extra attention is needed if the vehicle is heavily loaded, because a load lifts the beam. In a stationary queue, the Highway Code tells drivers to apply the parking brake and, once the following traffic has stopped, take the foot off the footbrake so the brake lights do not glare into the car behind.

Section 4 of the DVSA car and passenger vehicle manual is the lamps chapter. Mandatory headlamps are a matched pair of main beam and a matched pair of dipped beam, which can be the same pair. A missing or inoperative mandatory headlamp is a major defect. For LEDs, more than half the light sources not functioning is a major defect, and up to half is minor. Aim outside the published limits is a major defect. The tester checks European-type lamps on dipped beam and British American types on the beam the manual specifies.

Colour must be white, predominantly white with a blue tinge, or yellow. Converting an existing halogen unit on a vehicle first used on or after 1 April 1986 to HID or LED bulbs, rather than fitting a complete replacement unit, fails as light source and lamp not compatible. Manual levelling devices must work from the driver's seat. Headlamp washers are inspected on vehicles first used on or after 1 September 2009, and an inoperative washer on HID or LED systems is a major defect.

Using a vehicle without the lights the Lighting Regulations require is an offence. GOV.UK's vehicle safety page also states that driving a vehicle in a dangerous condition can bring a fine of up to £2,500, a ban and 3 penalty points. This page does not invent a separate fixed penalty amount for a lighting offence, because the GOV.UK pages cited here do not publish one. A prohibition notice can take the car off the road until the lamps work.

DVSA officers can stop vehicles on all roads, including motorways, under Highway Code rule 107. They flash amber lights and direct you to a safe place. It is an offence not to comply. A lighting defect found there is the same defect it would have been in a car park, with the added fact that you were using the vehicle on the road.

Rules 113 to 116 apply to drivers and riders. A van has the same night and visibility duties as a car. A motorcycle has extra construction rules in the motorcycle MOT manual, but the Highway Code duty to use lights at night and in poor visibility still applies. A heavy load that aims the beams into the next driver's eyes is an adjustment problem Annex 6 already flags: adjust the lamps or the load.

A left-hand-drive car can use masks or converter kits to remove the dip kick-up to the right so the beam does not dazzle on UK roads. The MOT manual accepts that temporary alteration. Hire cars, company cars and courtesy cars do not carry a lighting exemption. If you drive it after dark on an unlit road, the headlights have to be on.

The Lighting Regulations and Highway Code rules 113 to 116 are Great Britain rules. Wales changes the usual restricted-road speed to 20 mph, and rule 113 mentions that 20 mph figure when it describes lit street-lit roads. The headlight duty itself does not change at the Welsh border. Scotland uses the same GB rules. Northern Ireland publishes its own Highway Code lighting text on nidirect. Use that for an NI argument.

Hazard warning lights, which people mix up with headlights, have their own rule 116: you may use them when stationary to warn that you are temporarily obstructing traffic, and you must not use them while driving or being towed unless you are on a motorway or unrestricted dual carriageway and need to warn drivers behind of a hazard ahead. That is regulation 27 as well, and it is not a substitute for headlights.

Driving on daytime running lights after dark, because the dashboard looks lit and the front of the car looks lit, while the rear is dark. Leaving main beam on for a cyclist, a horse or a crest. Fitting cheap LED bulbs in halogen reflectors and then failing the MOT for an incompatible light source. Forgetting that a loaded boot aims the lamps up. Treating a fog warning sign as a reason to use fog lights instead of headlights.

The fix is a walk-round at dusk once a week: sidelights, dipped beam, main beam, indicators, rear plate lamp, and a look at the aim against a wall. If a lamp is out, it is out today, not at the next MOT. Replace it before you use the car on an unlit road. Carry a spare bulb if the handbook still treats bulbs as user-serviceable. Many modern lamps are not, which means a dead lamp is a garage job before the next night drive, not a lay-by repair.

Stop as soon as it is safe. A single inoperative mandatory headlamp is already a major MOT defect, and using the car on an unlit road with one lamp is using it without the lights the Regulations require. Hazard warning lights are not a substitute while you keep driving. Rule 116 allows them while driving only on a motorway or unrestricted dual carriageway to warn of a hazard ahead, and only long enough for that warning to be seen.

If you can change the bulb without putting yourself in the carriageway, do that. If you cannot, get the car recovered or wait for daylight on a lit road. A prohibition at the next encounter is the enforcement version of the same advice. For HID and LED units, do not touch the high voltage parts. That is a workshop job, which the MOT manual also flags because those lamps take seconds to reach full intensity and run at high voltage.