Fall and Winter: More Light on the Streets
Author: Joachim Geiger
Properly functioning vehicle lighting gives the driver as well as other road users increased visibility. However, safety campaigns in fall regularly reveal that this is not always the case. DEKRA accident researcher Stefanie Ritter explains why everyone should take care of proper vehicle lighting.
“Road safety is always also a question of the visibility of each road user,” the accident researcher explains. Drivers are well advised to keep their vehicle lights in the best possible condition, especially when driving at dusk and in the dark. “Anyone driving with inadequate lights can cause dangerous situations and accidents, especially in the fall and winter,” says the DEKRA expert. In fact, at this time of year headlights are often glaring, defective or 'one-eyed', as road safety campaigns in countries such as Germany, France, Luxembourg and Austria regularly bring to light.
One of the biggest campaigns of this kind is the so-called 'Licht-Test' in Germany, that has been organized by the Central Association of the German Motor Trade (ZDK) and the German Road Safety Association (DVW) every October for almost 70 years now. This annual light test takes place in workshops and DEKRA branches across the country where the institutions offer free lighting checks. The results of these campaigns are mixed for car owners: The 2023 light test statistics show that more than one in four cars (27.4 percent) had lighting defects. At 18.7 percent, the headlights occupy first place in the defect statistics. Although it is the exception rather than the rule that a headlight fails completely (3.4 percent), the proportion of vehicles with headlights set too high is 8.5 percent and 7.7 percent with headlights set too low.
The low beam is the most important visual aid for drivers in the dark
“If you check your lighting system regularly, you will drive much more safely,” says accident researcher Stefanie Ritter. A correctly adjusted low beam illuminates the road well and makes it possible to recognize pedestrians and cyclists on the road, as well as other vehicles and obstacles, at an early stage. To a certain extent, the low beam is the driver's most important visual aid at dusk and in the dark - so it is only logical that a defective headlight restricts visibility when driving. But that's not all: a “one-eyed driver” is less visible to oncoming traffic or is perceived as a motorcycle. Incorrect headlight adjustment can also have unwanted consequences. If the lights are set too low, it is at the expense of visibility and the range of vision, because the illuminated area in front of the vehicle is reduced accordingly. On the other hand, headlights that are set too high can severely impair oncoming traffic's unobstructed view due to glare. This can be particularly dangerous in the dark or in the rain. “In the veil of glare, contrast is lost for the glare-obscured driver. Often they can no longer see anything other than the light source and therefore cannot react to pedestrians or vehicles at the side of the road,” the DEKRA expert adds.
Diffuse lighting conditions can overwhelm the sensors of an automatic lighting system
Having optimum lighting is a life insurance policy for the driver. After all, driving at night is a stressful experience for the eyes due to the high level of concentration, poor visibility and glare from oncoming traffic. Headlights can compensate to at least some extent. Modern cars with automatically dipped headlights in particular can make life a little easier for the driver, as the automatic system automatically switches on the low beam when dusk sets in. And what if rain, fog or snowfall obstruct visibility? In this case, it is imperative to drive with the lights on. However, automatic light sensors are often unable to cope with diffuse light conditions, which can also occur in fog or when entering a tunnel: The automatic system often reacts late or not at all. In these cases, the driver has to switch on the lights manually.
In fall and winter, low beam ensures better visibility during the day
As DEKRA expert Stefanie Ritter explains, low beam lights are a plus for safety on cloudy days in fall and winter: “If drivers also switch on their low beam lights during the day, their own vehicle is easier for others to see - the risk of being overlooked is reduced.” On the other hand, even well-functioning lighting requires a certain amount of care.
Driving on fall or winter roads can quickly turn headlights and tail lights into dirt traps, making vehicles less visible to other road users. Solving the problem is not rocket science: “A quick visual inspection before driving and a damp cloth for cleaning can significantly improve safety,” says accident researcher Stefanie Ritter.
As the Federal Statistical Office explains in its analysis “Road traffic fatalities in the EU”, fatal accidents involving pedestrians are particularly frequent in the darker months of the year. The current accident statistics for Germany for 2023 again show that dusk and darkness are a challenging time for the safety of road users: Almost a third of all accidents with fatalities occurred at this dark time of day. Pedestrians are the weakest link in the accident chain, while the roads most prone to accidents in the dark are rural roads and highways. “Functioning and switched-on vehicle lighting is therefore extremely important in order to avoid such accidents, says accident researcher Stefanie Ritter. “However, all road users - drivers and pedestrians alike - are called upon to ensure greater safety: pedestrians can significantly improve their visibility by wearing bright clothing and retro-reflective elements.”
- The low beam is the most important light source in a car. It illuminates the road and helps the driver to recognize obstacles at an early stage. Defective or incorrectly adjusted low beam lights can significantly reduce visibility.
- Headlights should be optimally adjusted so that oncoming traffic is not unnecessarily glared at in the darker months of the year. The headlight settings are also checked during the light test. This includes checking whether the headlights are set too high or too low.
- On cloudy days in the fall and winter, drivers have a safety advantage if they also switch on the low beam lights during the day. This makes it easier for others to see one's own vehicle, reducing the risk of being overlooked. If rain, fog or snowfall obstruct visibility, you should also drive with your lights on during the day.
- Marker lights (parking lights) and daytime running lights are no substitute for dipped headlights. When dusk sets in at the latest, it's time to turn on the lights. Only those who are clearly visible to others are safe on the road.
- Automatic headlights are a practical convenience function. However, the driver should not rely on the system working perfectly in all conditions. In poor visibility conditions during the day, the low beam should therefore be switched on manually for safety reasons.
- The high beam is used to increase visibility at night. It illuminates the road further than the low beam and therefore provides better visibility in poor light conditions and on unlit roads. On roads with sufficient lighting, the high beam must remain switched off. Dip your headlights in good time if a vehicle is approaching or driving a short distance ahead.
- If your vehicle is equipped with automatic high beam, you should be aware that it does not always recognize oncoming vehicles - in this case you must switch off the high beam manually.
- The high beam does not help in fog. On the contrary: it is refracted thousands of times and reflected back to the driver. The fog lights only improve visibility directly in front of the vehicle. In general, the visual driving requirement also applies here - drivers must be able to stop within the clear distance.
- Rear fog lamps are an important safety feature in vehicles, which improve the visibility of the vehicle for following road users in fog or when visibility is severely restricted. However, if they are switched on in normal visibility conditions or in light fog, they can be extremely blinding for other road users. They should therefore only be switched on when visibility is below 50 meters and the speed is a maximum of 50 kilometers per hour. When visibility improves again, rear fog lights should be switched off so as not to dazzle following drivers. In countries such as Germany, such recommendations are even mandatory.
- If the vehicle is loaded, you should adjust the level of the headlights so as not to glare oncoming traffic.
- Tail lights and brake lights are essential for communicating with vehicles in the rear. Failure of the lights significantly increases the risk of rear-end collisions.