4x4 PROFESSOR

The law regarding headlights is not as clearcut as you might think – there are a number of regulations to consider. Regulation 159 of the National Road Traffic Act states that a vehicle’s headlight may not be higher than 1,4 m above the road surface and not lower than 450 mm. A headlight must also be within 400 mm of the side of the vehicle. (This excludes motorcycles and three-wheeled vehicles, of course.)

A vehicle may have one main light on each side at the front, and it may alternate between a main beam and a dimmed beam. (See illustration 1.) A vehicle may also have on each side at the front one main light that casts a main beam plus one light that only casts a dimmed beam. (See illustration 2.) A vehicle may have on each side at the front one headlight capable of casting only a dimmed beam plus two headlights capable of casting only a main beam. (See illustration 3.) A vehicle may have one main light on each side at the front that can alternate between a main light and dimmed light, plus one light that can only cast a main beam. (See illustration 4.)

The wording of this legislation can be interpreted as you being allowed a maximum of six headlights (see Figures 3 and 4) at the front of your vehicle.

Regulation 160 of the same legislation states that a headlight’s main beam must enable the driver to see another vehicle, person or significant object at least 100 m away in the dark. A headlight must also have a switch that allows you dim or turn the main beam on and off.

Regulation 161 discusses the characteristics of the dimmed light using the following formula: {{(h_1 ~ - ~ h_2)} over L} ~ x ~ 100, but also where exactly the beam falls on the road surface according to the formula 200 x h1. We’re not going to do calculations here – it’s enough to know that if there is a SANS or E symbol on your vehicle’s headlight, it should meet the law’s requirements.

What about spotlights?

This is where things get, well, a little murky. The law’s view of what the word ‘spotlight’ means is probably different to your understanding of the word.

The legislation speaks of a spot lamp. According to regulation 177, a spot lamp may not be adjustable to shine in any direction unless it is mounted on an ambulance, rescue vehicle, fire truck, police or traffic vehicle. A direction-changing spotlight may also be used by a lifeguard and veterinarian, as well as a towing or repair service that performs essential services (such as electricity supply) – and then the lights may only be used at the scene of the service. This legislation seems to be opposed to the adjustable spotlights used by hunters and rangers, and at one stage also by 4x4 enthusiasts.

Regulation 185 concludes that only the lights discussed above may be fitted to your vehicle. The conclusion is that you may put one pair of spotlights (as we know it) on your vehicle, provided that they comply with the requirements of regulation 159. In other words, a vehicle may have one main light on each side of the front that can alternate between main and dimmed, plus one that can only shine a main beam (your spotlight). It must be within 400 mm of the side of the vehicle and not higher than 1,4 m or lower than than 450 mm from the road surface.

Exceptions were made for the Nissan X-Trail that came out of the factory with spotlights on the roof, but that’s another matter.

Unfortunately, the wording of the legislation is clumsy and doesn’t keep up with technology. For example, the regulations refer to a light as a lamp, in singular form, which is interpreted by traffic authorities as one light bulb. This is an interpretation that is often backed by magistrates, which is why a cop may fine you for using LED spotlights that technically consist of dozens of lamps – regardless of whether it has the E or SANS marks. Yet LED daytime running lights – on every modern car – are weirdly not considered a violation.

This is why traffic officials aren’t consistent in the application of the law. The fact is there is no clarity on spotlights. A reasonable traffic officer will allow one pair of LED spotlights on your off-roader, but consider yourself lucky if you’ve been through a roadblock without getting a fine for an LED light bar on your roof.

Cool, neutral or warm?

There are three main categories for headlights: filament, xenon and LED. These lights shine at different colour temperatures (no, it has nothing to do with heat) that alternate between yellow and turquoise. We measure the colour temperature with units of Kelvin (K).

Filament lights are the oldest and use tungsten filament and halogen gas to cast a warmcoloured light (4 000 K). Xenon lights, also known as HID lights, shine a bright, cool light (6 000 K) that alternate between white and slightly turquoise. LEDs are the latest on the market and you get them in different degrees of brightness and different colour temperatures.

The warm light created by tungsten and halogen may not be extremely bright, but it creates more contrast in the dark so you can more easily spot a kudu next to the road. It also provides better depth perception and is less likely to tire your eyes.

The cold light of xenon lights packs a punch and you can see farther with these kinds of lights than with halogen lights. Unfortunately, it also reduces contrast and colour saturation, which can sometimes make it more difficult to spot an animal. They are also massive annoyance for oncoming traffic because they are so bright – and therefore often declared illegal.

LEDs are almost as bright as xenon lights, but they use less power, have a longer life than halogen and xenon,

Some history

William Thomson was a British mathematician at the University of Glasgow who became famous for his first and second law of thermodynamics as well as the determination of absolute zero at -273,15 °C. After Queen Victoria knighted him in 1866, he was given the title of Baron Kelvin – after the Kelvin River near Glasgow.