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While most owners work hard not to damage their car, buyers of the new Mercedes-Benz CLS would do well to avoid a front-end impact through fear of damaging the active LED headlights.

If a kangaroo strike or a shunt in traffic damages a headlight, owners may have to be calmly seated and away from loved ones when they get the replacement bill.

The advanced "Intelligent Lighting System" lamps cost "about €3000 each" to replace, which amounts to something in the order of $5000 each.

So, just at the front of the new Benz four-door "coupe" there are about $10,000 worth of lights. Add to that advanced interior lighting and the curvaceous tail lights and this Mercedes-Benz has about a three-door hatchback-worth of lighting on board, amounting to about 10 per cent of its $150,000-plus price tag.

Audi was the first to introduce full LED lights on its latest A8, which it claimed would "herald a new chapter in the history of lighting technology".

But the lights in the new CLS take the technology a step further, able to adjust to oncoming traffic, peer through corners, illuminate more brightly, save fuel and even modify a beam in thick fog.

Each bulb is essentially a tiny patch about the size of a grain of rice, housed within a lens that projects the beam in the required shape and direction.

The lights are more efficient than regular filament globes and even more efficient than expensive xenon beams, which also project a toothpaste-white beam.

Total drain on the electrical system is a little more than 40 watts from each light, helping reduce fuel use. They should also last the life of the vehicle.

Clever lenses and reflectors can direct the lights in the required direction, while computer-operated swivels can adjust the beam from low to high and turn the reflector to turn through corners.

Mercedes-Benz is already working on the next generation of LED headlights.

Crucially, they will be designed to be repaired more easily, meaning front-end damage may not result in such hefty repair bills, which can increase insurance premiums.

The next-generation lights will also use more advanced systems for detecting oncoming vehicles.