September 15, 2004

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Feature:
What's new in automotive lighting
by Tony Whitney

There's no doubt that today's vehicles are equipped with the best lights in automotive history, whatever their function, but it wasn't always that way. Early automobiles were fitted with very inefficient oil lamps, much the same as those used on horse-drawn vehicles of the day. Thankfully, vehicle speeds were modest enough to make that old lighting just about adequate, but as power increased and motorists got used to quicker journeys wherever they went, lighting steadily improved - but progress was slow.

Older readers will remember the days of dim and ineffective sealed beam units that barely showed the way at half the speed limit and were downright dangerous if you needed to drive fast. Back in the 1970s and 1980s, I remember that the first thing I usually did when I took delivery of a new car was to get rid of the sealed beams and fit a decent set of halogen headlights. The difference was amazing and the safety benefits beyond cost, but there were still a few police officers around who'd write you a ticket if they thought them too bright.

Thankfully, times have changed and your new car is likely to be equipped with lights that offer safety at whatever speed the law allows. Modern headlights are complex and sophisticated pieces of engineering - especially if you have an upscale model with the latest xenon units. Xenon lights can be set up to provide amazing down-the-road visibility without distracting oncoming drivers.

Of course, efficient lighting is not simply characterized by beam brightness - there are other advancements in place now, as typified by the new BMW 6-series models. BMW has always taken a lot of trouble to get its lighting just right, so the Bavarian automaker is a good example of current technology.

The new 6-Series is fitted with headlights that actually "see around corners" and the safety benefits are impressive. Of course, many auto enthusiasts will remind BMW that there's "nothing new under the automotive sun" and that Citroen had movable headlights decades ago. That may be the case, but BMW has taken the idea several stages further.

Called "Adaptive Headlights" by BMW, the lights swivel around on their vertical axis and point around bends on winding roads. The system uses a pair of bi-xenon swivelling reflectors which work in conjunction with a pair of fixed halogen high beam reflectors. That way, the driver can see around the next bend without any interruption to the function of the fixed high beams. BMW claims that the system improves illumination of the road ahead by 90 per cent and this is certainly possible.

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The swivelling reflectors move around their axis as a function of the car's steering angle, its yaw rate and road speed. The engineering people at BMW must have worked hard at this technology because it's very complex and must function perfectly at all times.

Included in the set-up is a full headlight cleaning system, so owners of this expensive and upscale coupe should never have to worry about seeing their way on the darkest of nights and on the twistiest of roads. Not surprisingly, rival automakers have been working on similar systems and I wouldn't be surprised to see a simplified version on more affordable products a couple of years down the road.

The designers of BMW's stylish new model didn't stop at the front lighting when it came to technological advancement. The car features tail and brake lights that use LED (light emitting diode) technology for improved performance and reduced risk of accidents from behind. LEDs are brighter than conventional bulbs and they also respond faster and need no maintenance at all. Service life is reported to be very lengthy indeed.

A further lighting advancement on this new car is a brake force display system which involves the brake lights illuminating in two stages, according to braking intensity. What this basically means is that a driver following a BMW 6-Series can tell whether the driver is applying the brakes normally to check speed, or heavily, as if during an emergency stop. Though fairly simple, this dual-level braking system would seem to be a very significant safety development that could benefit all drivers if it enjoyed wide use.

Although today's automotive lighting systems (and "systems" is the only word for some of them) are complex and expensive, they do enhance safety considerably. And as with so many other advancements in the auto industry, they may now be available only on premium models, but are more than likely to filter down to less expensive products fairly quickly. That's just what happened to the halogen lights that seemed so "state-of-the-art" back in the 1970s.