Why Shouldn't High Beams Be Used in Rainy Weather?
3 Answers
Using high beams while following another vehicle in rainy conditions can obstruct the leading driver's visibility, increasing the risk of accidents. Additional information: 1. High beam overview: The intensity of light is adjusted based on the distance between filaments. High beams focus light at their focal point, emitting parallel rays that are highly concentrated and bright, capable of illuminating distant and elevated objects. Low beams operate beyond the focal point (between 1x to 2x focal length), emitting divergent light that illuminates a wider area at closer range. 2. High beam usage regulations: Traffic laws permit high beam use on unlit roads when vehicle speed exceeds 30 km/h at night. Therefore, high beams are allowed on highways. However, drivers must immediately switch to low beams when approaching oncoming traffic or closing distance with preceding vehicles on undivided highway sections at night.
The other night, I was driving with a friend in heavy rain and made sure to turn off the high beams. Using high beams in the rain is especially problematic—the light reflecting off raindrops creates a white fog, making it feel like looking through frosted glass. Once, an oncoming car had their high beams on, and I was instantly blinded by the intense light, nearly scraping the guardrail. Rain and water droplets on the windshield scatter the bright light, blurring the entire field of vision, and road reflections become even more glaring. Low beams are sufficient on rainy nights; if you really need to see ahead, turning on the fog lights can help cut through the rain. Remember to adjust the rearview mirror to anti-glare mode, keep the wipers running, and maintain a longer following distance than usual for safety.
When I was taking my driving test, the instructor repeatedly emphasized: using high beams in the rain is equivalent to suicide. Water droplets act like prisms, scattering the intense light and creating a glare that blocks visibility. The most dangerous scenario is when headlights shine on wet roads, as the glaring reflections completely obscure potholes and road markings. Experiments show that in rainy conditions, the effective visibility distance with high beams is 20 meters shorter than with low beams. Experienced drivers know that driving on rainy nights requires turning on the front and rear fog lights in advance—these are specifically designed to penetrate rain and fog. When the rearview mirror is covered with water droplets, high beams turn it into a flash grenade, making it difficult to see approaching vehicles from behind.
