When to Use Fog Lights in New Zealand: The Rules and Common Misconceptions

In New Zealand, fog lights are for fog, mist and other conditions where visibility is seriously reduced, and should be switched off at all other times. That is the position under the Land Transport Rule: Vehicle Lighting 2004 and the Road Code, published by NZ Transport Agency Waka Kotahi (NZTA). There is no New Zealand “100 metre” test like the one in the UK Highway Code, so if you have read a British guide, forget that number. This guide covers the New Zealand rule, what it means in rain and snow, why fog lights must go off when the fog clears, the dashboard symbols, how NZ Police enforce it, and how the rules apply to tractors and farm vehicles.

The New Zealand Rule: Fog and Poor Visibility Only

The Road Code says fog lamps are for use in fog or similar conditions where visibility is restricted, and should not be used at other times. That is the test for front and rear fog lamps alike.

Three points sit inside the rule. Fog, mist or similarly restricted visibility means fog lights may go on. Anything else means fog lights should be off. The driver judges the moment of switching based on what they can see ahead.

The rule is about real loss of visibility rather than a set distance, so a heavy shower or spray from the road does not on its own justify fog lights. Light mist or patchy fog that leaves you with a good view of the road ahead does not count either.

The reason is the same as anywhere else. In thick fog the road ahead can fall inside your stopping distance, and other drivers need every chance to see you. Outside those conditions, fog lamps cause more problems than they solve.

For the wider auxiliary lighting picture, see Fog Lamps Explained and Fog Lamps, DRLs, and Auxiliary Lights pillar.

What the Road Code and NZTA Say About Fog Lights

The Road Code deals with fog lights in its sections on lights and on driving in bad weather, and NZTA’s Vehicle Inspection Requirements Manual sets out how fog lamps are checked at a WoF or CoF. Both apply to all road users, including farmers, contractors and drivers of agricultural vehicles.

For driving in fog, the Road Code advises using dipped headlights, reducing speed and keeping a safe distance from the vehicle in front, with fog lamps as an addition where they are fitted.

Three obligations come out of the New Zealand guidance. Use dipped headlights in fog. Use fog lights only when visibility is seriously restricted. Turn fog lights off when conditions improve.

Lighting rules in New Zealand come from the Land Transport Rule: Vehicle Lighting 2004, as amended. The Road Code is a plain-language guide rather than the law itself, so if you need the exact legal wording, check the rule and NZTA’s current guidance.

For the underlying regulations, see the New Zealand lighting rules and Tractor Road Legal Lights.

Can You Use Fog Lights in Rain or Snow

Heavy falling snow can cut visibility as badly as fog, so fog lights may help while it lasts. Rain is different. Heavy rain on its own does not usually justify fog lights.

The trigger is the condition, not how gloomy the day feels. Snow driving into the windscreen on a high country road can restrict visibility enough to count. A wet June evening on a rural road, however grim, is not fog.

Three scenarios show the rule in action. Steady drizzle on the way to the saleyards means fog lights stay off. Thick fog or heavy snow on a back road means front and rear fog lamps may switch on. Snow stopping, or fog lifting, means fog lights must switch off again.

A common driver error is switching on rear fog lamps in steady rain to “be seen better”. That is not what they are for. The rear fog lamp produces 150 to 300 candela of red light, bright enough to mask the vehicle’s brake lights from the driver behind. Dipped headlights and rear lamps are the right lighting in rain.

For the rear fog lamp specification, see Rear Fog Lights: Regulations and Fitment.

Why You Must Switch Fog Lights Off When Visibility Improves

The rule is clear: fog lights should be off at all other times. Fog lifts in patches, and the driver who keeps fog lights on through clear stretches breaks the rule and creates a risk for others.

Three problems follow if rear fog lamps stay on in clear conditions. Drivers behind cannot tell brake lights from rear fog lamps, because the rear fog produces 150 to 300 candela compared to the brake light’s 60 to 185 candela. Drivers behind suffer glare from the high-intensity red light, which slows their reactions. And the driver in front is using a lamp outside the conditions the rule allows.

Two problems follow if front fog lamps stay on in clear conditions. Oncoming drivers get glare from the wide, low-mounted beam. The vehicle’s headlamp pattern becomes confusing, because the front fog beam adds light below the dipped beam cut-off and undoes what the dipped pattern is designed to do.

The driver should re-check conditions every 30 to 60 seconds in shifting fog. Fog in valleys and low-lying ground can clear in seconds. The rule does not allow “I might need them again in a minute” thinking. Fog lights off when the fog clears, on again only if it closes back in.

How to Recognise the Fog Light Symbols on the Dashboard

Vehicles show fog light status with two distinct dashboard symbols. The front fog symbol is a green icon showing a forward-tilted lamp with three downward wavy lines. The rear fog symbol is an amber or yellow icon showing a backward-tilted lamp with three downward wavy lines. The wavy lines represent fog cutting across the beam.

Three features distinguish the two symbols. Colour, green for front and amber for rear. Direction, the front symbol points right (forward from the driver’s view), and the rear symbol points left. Position, the front fog tell-tale sits with the headlamp indicators, and the rear fog tell-tale sits with the warning lights.

The rear fog tell-tale is a type-approval requirement. ECE Regulation 38 requires every vehicle with rear fog lamps to have an amber tell-tale visible to the driver. The tell-tale only goes off when the rear fog lamp goes off. It exists to remind the driver that the rear fog lamp is on, because it is so easy to forget after fog clears.

Front fog tell-tales follow the same logic. Most vehicles fit a green tell-tale that lights when front fog lamps are on, and most manufacturers fit one as standard.

The driver should check both tell-tales every time the lights stalk moves. A glance at the dashboard confirms which lights are on and which are off.

Enforcement of Fog Light Misuse

Fog light misuse is enforced by NZ Police. Using lamps in a way that dazzles or confuses other road users is against the lighting rule, and lighting offences can lead to an infringement notice. Check NZTA’s current guidance if you need the detail of a particular offence.

Where fog light misuse dazzles another driver or contributes to a collision, more serious charges can follow, such as careless driving. Defective lamps also matter: front and rear fog lamps are generally optional, but if fitted they must work and meet the rules, or the vehicle can fail its WoF or CoF.

Check with your inspector before removing factory-fitted fog lamps, as changes to factory lighting need to meet the rules too, so taking them off to avoid the issue is not the answer.

A driver with rear fog lamps blazing on a clear night stands out at a distance. Expect more attention in autumn and winter (March to August), when fog and short evenings come together.

For the wider regulatory framework, see Tractor Lighting Regulations.

Fog Lights on Tractors and Farm Vehicles

Fog light rules apply equally to tractors, self-propelled machines and agricultural trailers on New Zealand roads. The fog and poor visibility rule applies to a tractor driver in the same way it applies to a car driver.

Three points apply specifically to tractors. The lighting a tractor needs on the road at night (headlamps, position lamps, rear lamps, stop lamps, indicators and number plate lighting) must be fitted and working, and fog lamps are additional to that, not a replacement. Any fog lamp that is fitted should work. And amber warning lamps are required on agricultural vehicles in various situations, such as oversize or slow-moving operation, fog or no fog.

Front fog lamps on tractors are optional. Where fitted, they must show white or selective yellow light, meet a recognised standard such as ECE R19, and be mounted as the rules require (low on the vehicle and paired symmetrically). Check NZTA’s guidance for the exact mounting requirements.

Tractor drivers need to think harder about fog than most car drivers. A slow tractor on a road with an 80 or 100 km/h limit is at real risk of being run into from behind in fog, so dipped headlights, rear lamps, a beacon and (in thick fog) a rear fog lamp all help. Wide loads such as sprayers, mowers and balers need clear rear lighting, and a lighting board should be fitted if towed equipment hides the tractor’s lamps.

Common tractor fog light errors mirror car errors. Rear fog lamps left on after a road run in clear conditions. Front fog lamps used as makeshift work lights on the road (work lamps must be switched off on a public road anyway). Trailer rear fog lamps wired to the side lamp circuit, so they come on every time the side lamps do.

For the tractor-specific lighting law, see Tractor Road Legal Lights and Agricultural Trailer Lighting Requirements.

Common Misconceptions About Fog Lights

Five misconceptions about fog light use cause most of the problems. Each is wrong on the rules, the safety, or both.

Misconception 1. “Fog lights help me be seen in rain.” False. Ordinary rain is not fog. The rear fog lamp masks brake lights and the front fog lamp dazzles oncoming drivers. Use dipped headlights instead.

Misconception 2. “Front fog lights replace dipped beam in fog.” False. The front fog lamp supplements dipped beam, it does not replace it. The Road Code advises dipped headlights in fog, and type approval allows front fog lamps to work only with dipped or main beam on.

Misconception 3. “Rear fog lamps are like brake lights, the brighter the better.” False. Rear fog lamps mask brake lights when conditions are clear. The driver behind cannot see the brake light through the rear fog lamp’s higher intensity, which is exactly why use is limited to fog and similar conditions.

Misconception 4. “I can use fog lights at night for extra visibility.” False. A clear night is not fog. Headlights and rear lamps are the right lighting at night in clear conditions.

Misconception 5. “It is fine to keep rear fog on when towing a trailer in heavy rain.” False. The rule applies to towing the same way it applies to solo driving. The trailer’s rear fog lamp follows the same rule as the tractor’s.

The principle is simple. Fog lights are visibility tools for fog and similarly restricted visibility. They have no legitimate use outside those conditions.

Quick Reference: Fog Light Rules at a Glance

The New Zealand fog light rules come down to seven facts.

When allowed: Fog, mist or other conditions where visibility is seriously restricted.

Source: The Road Code and NZTA guidance, under the Land Transport Rule: Vehicle Lighting 2004.

Rain: Ordinary rain does not count. Use dipped headlights, not fog lamps.

Switch off: Turn fog lights off at all other times.

Dashboard symbol: Green for front fog, amber for rear fog. Both symbols show three wavy lines.

Enforcement: NZ Police, with infringement notices for lighting offences. Fitted fog lamps that do not work can fail a WoF or CoF.

Tractors and farm vehicles: Same rules apply, on top of the tractor’s required lighting and any amber warning lamps it needs.

For practical fog lamp choice, see Fog Lamps Explained and the rear fog lamp guidance at Rear Fog Lights Regulations. Browse current fog lamp options in the auxiliary lighting category on Agri Lighting.