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Which of your vehicle's lights do you have on if you are driving in fog? Which of your vehicle's lights do you have on if you are driving in fog?

  • A. Park lights (side lights)

  • B. Front and rear fog lights

  • C. Dipped headlights

  • D. All of the above

    The correct answer is D
    When you turn your lights on your park lights come on automatically. Don't use high beam lights because they'll reflect back off the fog and reduce your visibility - keep your lights dipped. Use fog lights if your vehicle has them fitted, but turn them off when the fog clears as they can dazzle other drivers.

What are fog lamps or fog lights?

When you drive in fog or heavy snowfall you must use your dipped headlights and fog lights.

Fog lights consist of one or two bright red rear lights and two low-mounted headlights. In Europe and other countries that adhere to UN Regulation 48, vehicles must be fitted with rear fog lights at minimum. They are less common on Japanese and American vehicles.

The intensity of a rear fog lamp is similar to that of a brake light, or stop lamp, and for this reason there is an argument that having two fog lamps is confusing to drivers following because it looks like activated brake lights. Some cars, such as many Peugeot models, have a centre-mounted fog lamp. Many older cars have one single fog lamp in the right-hand rear light with a reversing lamp in the corresponding place in the left-hand light. Newer cars conforming to UN Regulation 48 must have at least a 10cm separation between the closest illuminated edge of any fog light and stop light.

The disadvantage with a single fog lamp is that it is slightly more difficult to perceive the distance you are away from it.

Fog lights can be distracting and/or blinding to other drivers when there is no fog, so it’s important to only turn them on when required. It’s actually against the law in New Zealand to use your fog lights when it’s not either foggy or snowing, or visibility is significantly reduced in some other way, for example by smoke. If it’s clear you are not allowed to use fog lights at night, either.

The front-mounted lights are set low and give a short, wide beam of light to help illuminate the way without reflecting a lot of light back at the driver like full-beam headlights would. The centre line of the beam of light emitted from the lamp must be to the left of the centre axis of the vehicle, and they must be permanently dipped.

Front fog lights help the driver see the edge of the road more clearly. They also provide two extra points of light that oncoming drivers can see through the fog. In fact, front-mounted fog lamps must not be positioned higher than dipped-beam headlights on the vehicle. 

Vehicles are allowed a maximum of two front fog lights and two rear fog lights in New Zealand. The front ones must be white or amber and the rear ones must be red. There are approved standards that must be met.

Rear fog lights must be able to be turned on and off independently of the taillights.

What visibility levels should fog lights be used in?

You can find the specifications of fog lamps in rule 32005 Vehicle Lighting 2004 from the Ministry of Transport.

There are no definite directions about when to use fog lights. Road authorities in other countries suggest that a reduction in visibility to less than 100m means visibility is reduced enough to use fog lights, but 100m is difficult to judge when it's dark. The New Zealand rule specifically states:

Fog lamp means a high intensity lamp designed to aid the driver or other road users in conditions of severely reduced visibility, including fog or snow but not including clear atmospheric conditions under the hours of darkness, and that is: