We have long since moved beyond using only the standard high and low beam functions in a vehicle to illuminate the road. In an increasing number of vehicles, adaptive front lighting systems provide exactly the right light for a given driving situation. In its latest form – glare-free high beams – the driver has the best possible visual range at night, at all times, without dazzling other drivers on the road.

In terms of its light-distribution pattern, the low-beam light considered standard today originated in the late 1950s, when asymmetric low-beam light was introduced in Europe. Since then, the right-hand side of the roadway has been illuminated significantly more than the left, the side of oncoming traffic. Compared to symmetric low beams, this change enhanced safety tremendously.

However, in the meantime, the traffic situation and motor vehicles have advanced dramatically. Speeds are higher and traffic density has increased significantly. As a result, the use of classical high beams during long-distance trips has dropped to about 2% of total driving time. Although the range of the low beams has more than doubled since the introduction of asymmetric light, the low-beam light and its distribution in no way have kept up with speeds now common, for example, on highways. Furthermore, asymmetric light does not offer any advantages in cities, where a wide, symmetric beam pattern is best.

The introduction of projection systems or lens headlamps made it possible to better control light distribution patterns to a great extent. After the turn of the millennium and approval by the authorities, the market introduced the first vehicles that were able to adapt their light to the driving speed. At standard city speeds, a wide “carpet” of light offers considerably better visibility of what is going on beside the road. Pedestrians are easier to see and, when turning a corner, more light than before falls in the new direction of travel. At inner-city speeds, the light does not need to have as long a range compared to what is needed for highway driving.

The situation is different on country roads. In many countries, drivers are obliged by law to drive at a speed that allows them to stop within the visibly clear distance ahead. If this principle is strictly applied, then a car using low-beam lights with today’s standard range never should travel any faster than 50 mph (80 km/h), even with the best headlamps.

But reality often is different in traffic today. Most severe accidents and traffic fatalities occur on country roads, and the numbers that occur at night are disproportionately high. Better light is a critical countermeasure, but first-generation adaptive front-lighting systems are not enough, because they have only standard low beams for country driving. Only the latest solutions with glare-free high-beam light offer greater visibility.

The situation is different yet again under highway conditions. While adapting speed to the visibly clear distance ahead no longer is required by law under certain circumstances in some countries, the visual range of conventional low beams no longer is commensurate with high speeds.

Headlamps with adaptive front-lighting systems raise the light slightly at highway speeds. The range of the headlamps increases accordingly, for another critical gain in safety. No one is dazzled by the light, because the distance to the car ahead likewise is greater in these traffic situations. Thanks to more widely spaced lanes, oncoming drivers do not suffer from the greater range of the highway beam pattern.