Kåre Rumar gained his Ph.D. in 1969 on a thesis about the human ability to see in the dark while driving. He was assistant professor of psychology at the Technical University of Uppsala, Head of Research, Professor and Deputy Director-General of the Swedish Road and Transport Research Institute (VTI) in Linköping, Traffic Safety Director at The Road Administration in Borlänge. He also guest researched in two years at the Transportation Research Institute, University of Michigan, USA, and has authored over 200 scientific publications, mainly treating vision in night traffic, and kept a
large number of lectures nationally and internationally.
 
Risk of an accident per driven kilometer in the dark is between two and ten times higher compared with daytime traffic, on average about twice as high but for some accidents as accidents involving pedestrians and single vehicle crashes, it’s about four times higher and for wild animals about ten times higher. Why is it so?
 
The major reason is the dramatically reduced visibility in night traffic. Human eyes are designed for natural light and works very poorly in the dark. The ability to identify weak contrasts are sharply reduced and the dazzling sensitivity is highly elevated. Car lighting is not good enough to replace the light our eyes are made for – sunlight that is. Until a strong beam gives the distance you want to see only 1 / 100000 of the sun's light. Even a good high beam dazzles oncoming drivers and reduces visibility further. For older drivers, this deterioration of vision in the dark is significantly greater than for younger ones.

Typical sight range to dark obstacles is with good halogen light (halogen lamp gives away three times as much light as the light bulb) about 50 meters for young drivers and about 40 meters for older drivers when meeting another car. In strong beam without meeting, the equivalent sight range over 200 meters for the younger and more than 150 meters for the elderly. Since we need at least 150 meters sight to drive somewhat safe these short sight ranges explain why accident risks in night traffic are much higher than in daytime where the visibility is only limited by the road curvature.

 
Many have tried to improve vision in the dark with different chemical and optical means but no one has succeeded. That leaves just to improve car lights. When I started studying car light, the light source was the old light bulb. The light was guided by the headlamp lens and the dipped beam’s light image was symmetrical. One could establish that since the car's childhood engine, brakes, steering, suspension etc improved significantly. Compared with this technical development, vision has developed very little. But during the last decade, xenon light (xenon lamp provides nearly three times as much light as halogen) and most recently light-emitting diodes (which draws much less power) has come and already had their breakthrough in more advanced cars. Today, light is optically controlled in high degree of reflectors design instead of with the headlamp. The most advanced lighting today does not just comprise high beam and dipped beam but different light images for different environments and conditions, like highway, road, street, curve, rain, etc.
 
The next evolutionary step will probably be that lighting becomes really intelligent - the car itself can adjust the light after current specific needs, taking the oncoming car's distance and lighting characteristics, traffic composition, the route and its characteristics, weather and road conditions into account. Not only the headlights will be intelligent, but also the various signal lights (where LEDs have broke through quickly) on the car, so for example, they should adapt to the overall light level and be stronger in the sunlight and weaker in the dark. Brake lights should not only indicate that the driver has the foot on the brake, but also how strong she brakes. Another promising development is electronic sight, e.g. infrared sensors, which can warn the driver for warm obstacles; humans and animals. An old but still hard to beat idea is polarized light, which makes it possible to run on the beam without dazzling.
 
One problem is that it is so difficult for drivers to assess how well a car’s lighting really is. Studies show that drivers often assess car light after how much light it's just in front of the car which is completely wrong, the lights must be further along the road. In all vehicle tests done in various newspapers, headlamps is unfortunately not tested in a serious manner. The exception is Swedish car magazine Vi Bilägare, which present a number of key characteristics of the headlights. (I have been involved in developing that test).
 
Against this background, it is strange that car buyers almost never get an opinion on the quality of a car’s lights, for example by making test runs in the dark.
 


Audi night test – limited number of places
In September, Audi Sweden will start to offer test driving of the latest models under conditions where light security is in focus. In addition to good lighting, there is a range of technical solutions that help drivers in the dark. As the instrument lighting that automatically adjusts the brightness so there is no dazzle, automatic de-dazzling when two opposite cars meet, headlamps following the road in curves for example. The first darkness test driving will take place during week 39 in Smista (Southern Stockholm) when Audi opens up its most modern car plant in Sweden. The opening night driving has a limited number of places and applications are made by e-mailing info@carwinism.se.