When and how to use your headlights

11 April 2024

The ins and outs of high and low beam headlights as well as fog lights.

Automated features in modern cars such as self-levelling headlights are designed to make this essential road safety system even safer. But with all that complexity, headlights have also become a little more confusing.

Here are some of the common causes of confusion and mistakes made when it comes to vehicle headlights.

What’s the correct way to use low and high beam lights?

Driving in rural and regional areas after dark can often be unnerving, especially when you’re not familiar with the roads and even more so in low-visibility conditions such as during heavy rain and fog.

Low-beam headlights are only required to illuminate the road ahead of the vehicle for at least 25 metres, whereas high-beam headlights must provide at least 50 metres of illumination.

When using your car headlights on a high beam setting, you need to switch them off the high beam setting when you’re within 200 metres of any vehicles ahead of you travelling in the same direction.

The same applies to any vehicles coming towards you. Once you’re within 200m, switch your high beam off to avoid dazzling the other driver. If the headlights of an oncoming vehicle are dipped, regardless of the distance, you should switch high beam off.

When overtaking another vehicle, you may briefly switch your headlights from low-beam to high-beam immediately before you begin to overtake.

At what time of day and night should you turn your headlights on and off?

The official ruling is that your headlights should be on when driving ‘during the hours of darkness’. This is defined as the hours falling between sunset on one day and sunrise the next day.

If you want to follow this rule to the letter you can look up the official times for sunset and sunrise, which can be found online at sites such as the Bureau of Meteorology. However, it’s better to just judge the conditions and visibility at the time. If it dark objects are becoming difficult to see at around 100m, it’s time to turn your headlights on.

Can you drive with your interior light on at night?

In Western Australia there are no penalties for driving with an interior light on in your car, whether it’s during the day or at night.

However, because an interior light can limit your vision of the road, particularly at night, it’s best to only use it while safely pulled over off the road.

Do you need to use your headlights when it’s raining?

Headlights must be switched on when driving in hazardous weather conditions that reduce visibility, including fog or mist.

The regulations don’t specify which headlights should be used, so you need to judge based on the conditions and on whether it’s most appropriate to use low-beam headlights, high-beam headlights or fog lights.

If it’s raining during the daytime but visibility is still good, then you don’t need to use headlights.

What about fog lights?

Fog lights are designed to spread their light low and wide, unlike headlights which throw their light more narrowly and further ahead of the vehicle. This can make fog lights distracting for other drivers when there’s no fog, smoke or rain.

Fog lights can also be inadvertently switched on because the switch for them in some vehicles can be positioned close to the headlight switch and not always be clearly marked.

It is illegal to use fog lights incorrectly. They should only be used during fog or other hazardous weather conditions that reduce visibility. When fog lights are being used, headlights should be switched off. Having both switched on at the same time is not permitted.

Daytime running lights

Daytime running lights (DRL) have become commonplace on many vehicles, from small hatchbacks, to utes, luxury cars, SUVs and electric cars.

They are designed to make cars more visible to other drivers and are also used as a styling feature by some manufacturers.

Research published by Monash University found that DRL fitment can reduce the overall risk of being involved in a non-nighttime multi-vehicle crash where vehicle visibility may be a crash factor. However, the light produced by DRLs as it becomes darker can confuse some drivers into thinking their headlights are switched on.

Increasingly bright digital instrument lighting in modern cars, which is on day or night regardless of which lights are on, can also give the impression that headlights are on.

In older vehicles, instrument lighting generally doesn’t turn on until the headlights (or at least parking lights) are on. So your dash lights are in darkness until your lights are on. In newer vehicles, where it’s possible to have the dash lights on but not the headlights, drivers don’t have a visual prompt.

Many modern cars have an auto lights-on function, so leaving your light switch on auto will ensure your headlights go on when they should.

Fitting after-market lights

It is possible to purchase and fit brighter aftermarket lamps to vehicles that were not originally equipped with HID or LED lamps. The maximum number of additional driving lights that can be fitted to a vehicle is four. An LED light bar is considered one light if all operate together.

It’s important to note that fitting LED globes or HID bulbs in a regular housing will not correctly disperse light, which could impact other drivers’ view of the road, in addition to not being ADR-approved.

On a vehicle where additional aftermarket headlights emit more than 2000 lumens and are not fitted with the self-levelling features required for this level of light intensity as well as a self-cleaning system, the vehicle may not be considered roadworthy.