What is the speed limit when visibility on the highway is below 100 meters?
4 Answers
When driving a motor vehicle on the highway under weather conditions with visibility below 100 meters, the maximum speed should not exceed 40 km/h. Here is relevant information: 1. Speed limits: Motor vehicles with a maximum speed below 70 km/h are not allowed on the highway. The maximum speed for small passenger vehicles should not exceed 120 km/h, motorcycles should not exceed 80 km/h, and other motor vehicles should not exceed 100 km/h. 2. Precautions: Do not hinder vehicles in the main lane when merging, strictly distinguish lane functions, maintain smooth traffic flow, adhere to speed limit regulations, maintain longitudinal distance between vehicles, do not reverse or make U-turns on the main lane, always hold the steering wheel firmly when driving at high speeds, and avoid large steering angles when changing lanes or overtaking.
During my last road trip in heavy fog with visibility under 100 meters, I specifically checked traffic regulations: the speed limit on highways drops to 40 km/h in such conditions, and you must turn on fog lights, position lamps, and hazard warning lights. The most critical rule is maintaining at least 50 meters from the vehicle ahead—my compact car had me gripping the wheel with sweaty palms. A reminder: always check exit locations via navigation beforehand. If visibility keeps deteriorating, exit the highway immediately—never stop in the emergency lane. A friend got rear-ended there last year, denting the bumper. Now whenever I see fog forming, I head straight to the nearest service area for a break.
I've been in long-distance freight transport for fifteen years and have encountered heavy fog with visibility under a hundred meters at least twenty times. In such conditions, trucks must strictly adhere to the 40 km/h speed limit and turn on fog lights and hazard warning lights in advance. Experience tells me that maintaining sufficient braking distance is the top priority—50 meters may not even be enough when fully loaded. I remember once on the Beijing-Hong Kong-Macao Expressway, the vehicle in front suddenly braked hard, and it was only because I kept a distance of nearly 100 meters that an accident was avoided. I suggest fellow truck drivers use weather apps to monitor areas prone to patchy fog in real-time, especially when crossing bridges, where reducing speed to 30 km/h is the safest approach.
The traffic regulations clearly state: when visibility on the highway is less than 100 meters, the speed limit is 40 km/h. It is mandatory to simultaneously turn on front and rear fog lights + position lights + hazard warning lights, otherwise a penalty of 3 points and 200 yuan is non-negotiable. Last year, while handling a chain-rear-end collision accident, it was found that seven cars collided due to speeding. A special reminder to new drivers: don't think you can drive faster during the day—sunlight refraction in thin fog is even more dangerous. Maintaining a distance of 50 meters is the minimum, and it is recommended to turn on the lane keeping assist system for added peace of mind.
