TÜV SÜD: Daytime running lamps are not enough in fog
TÜV SÜD: Daytime running lamps are not enough in fog
On the A8 at Merklingen, fog has reduced visibility to 100 metres and the automatic traffic signs instruct drivers to slow to 60 kilometres per hour. While the technology works flawlessly, the drivers vary widely in their reactions; some brake sharply in uncertainty, yet others continue blithely onward, vanishing into the fog. The diversity of responses from drivers is mirrored by the lack of concerted awareness over the use of car headlamps. When should fog lamps and rear fog lamps be used, and what about daytime running lamps? Experts from TÜV SÜD provide tips on how to make the safest progress when road visibility is impaired.
"Mass pile-up in thick fog" is unfortunately an all too common autumn headline. But the causes behind the events have remained unchanged for as long as car drivers can remember: inadequate braking distance between cars, excessive speeds, overestimation of driving abilities, incorrect lighting. These factors add up to accidents in fog that occur not only on motorways, but also on normal highways and even in built-up areas: "Fog patches may suddenly occur near rivers and in valley bottoms. Drivers on the road in autumn should always be prepared for them and adjust their driving style accordingly", advises Philip Puls from TÜV SÜD. This primarily means maintaining an adequate distance from other road-users, driving at moderate speed and switching on fog lamps – and rear fog lamps too if required. "But never brake suddenly without good reason – this is always a danger for the traffic behind you", warns Puls."A rear fog lamp should only be switched on when visibility drops to below 50 metres – and under those conditions, limiting the speed to no more than 50 kilometres per hour is essential!" Fog lamps can be switched on before this point, and are also advisable in conditions of poor visibility caused by heavy rain and snow.
Headlamps must always be dipped in fog, snow or rain to avoid incurring a 40-euro fine and three penalty points on the driving licence. Puls notes, "In these situations daytime running lampsare not sufficient, particularly because the rear lights are not activated when they are on." Most vehicles also have fog lamps which illuminate the area directly in front of the vehicle and the sides of the road, primarily as an aid to orientation. If visibility is severely impaired by fog, snow or rain, these bad-weather lamps can be switched on. However, fog lamps are not permitted under normal visibility conditions and will incur a warning fine of up to 35 euros if used.
Regulations governing the use of rear fog lamps are stricter; they may only be used when visibility drops to below 50 metres and, unlike front fog lamps, only in foggy conditions, since they are up to 30 times brighter than normal rear lights and would dazzle drivers in the cars behind under normal conditions. In addition, speed must be restricted to 50 kilometres per hour when rear fog lamps are in use. "In this situation roadside reflector posts, which are generally positioned at 50-metre intervals, are useful for orientation", explains TÜV SÜD specialist Puls, adding, "But be sure to switch off the fog lamps again once visibility improves to over 50 metres." Drivers who leave rear fog lamps switched on after the fog hazard is past will risk a fine of up to 35 euros.
Incidentally in foggy conditions full-beam headlamps are counter-productive because the tiny water droplets in the air reflect the light and make a pea-souper fog even more impenetrable. However, windscreen wipers are useful for clearing the windscreen of the coating of moisture left by the fog.
Contact: Frank Volk