How far does the low beam shine?

Most new cars on the road today have headlights that illuminate the road beyond the legally required distance of 30 meters for low beam. However, it remains a legal requirement that low beam headlights must illuminate the road at least 30 meters ahead. I will explain why it's important to reduce your speed to 40 km/h on an unlit road before switching from high beam to low beam. Your stopping distance should always be within your sight distance. This means you should not drive faster than you can react and bring the car to a stop within the area that you can see in front of you. At 40 km/h the braking distance is approximately 16 m. The formula for the braking distance is 40 km/h X 0.4= 16 meters. Reaction time at 40 km/h is approximately 11 meters. The formula is 40km/h : 3.6 = 11.111 Stopping distance is the sum of a reaction distance of 11 meters and a braking distance of approximately 16 meters, resulting in a total stopping distance of about 27 meters. If you drive a car that meets the legal requirement for low beam headlights, which must illuminate the road for at least 30 meters, it would be irresponsible to drive faster than 40 km/h on an unlit road. This is because you need to ensure that you can stop the car within the distance that the low beam lights illuminate, which is approximately 30 meters. Given this illumination, the stopping distance for a car that just meets these legal requirements is about 27 meters. Your stopping distance must be within your sight distance, and you are required to adjust your speed so that you can stop for any foreseeable obstacles. Therefore, it is correct to slow down to 40 km/h in such conditions.