What is the maximum speed for turning and making a U-turn downhill?
4 Answers
When driving downhill, turning, or making a U-turn, the maximum speed should not exceed 30 kilometers per hour. The following are precautions for driving motor vehicles: 1. Special vehicles: When the vehicle in front is turning left, making a U-turn, or overtaking, or when the vehicle in front is a police car, fire truck, ambulance, or engineering rescue vehicle performing a task, overtaking is not allowed. 2. Oncoming traffic: If there is a possibility of encountering oncoming traffic while overtaking, overtaking is not allowed. 3. Intersections: When passing through railway crossings, intersections, narrow bridges, curves, steep slopes, tunnels, pedestrian crossings, or sections with heavy urban traffic where overtaking is not permitted and the speed limit is 30 kilometers per hour or less, overtaking is not allowed.
I always prioritize safety when driving, and I never take U-turns on downhill curves lightly. Traffic regulations clearly stipulate: the maximum speed limit for U-turns on urban roads is 30 km/h, but the actual safe speed for downhill sharp turns is much lower than this. A few days ago, I was driving on a mountain road, and when I took a downhill curve at just 20 km/h, the car started to feel unstable. I recommend keeping the speed between 10-15 km/h in such conditions, as the car's inertia is much greater downhill, and the turning radius is significantly larger than on flat ground. Even a slightly higher speed can easily cause the car to run off the road or scrape the guardrail. I remember once seeing a novice driver attempting a U-turn on a steep slope at 20 km/h—they almost hit a tree and had to make several quick steering corrections to recover. It’s really not worth risking those few seconds; getting home safely is what matters most.
Vehicle performance and physical laws determine that the maximum speed in such road conditions is difficult to exceed 20 km/h. I have specifically tested the downhill turning performance of different vehicle models: sedans start to experience significant tire grip reduction at around 15 km/h, while SUVs are more dangerous due to their higher center of gravity and are prone to rollover at speeds above 10 km/h. The most troublesome situation is during U-turns when centrifugal force combines with gravity, weakening rear-wheel grip and making understeer particularly noticeable. In the past, when driving an older car on a wet and slippery slope during a turn, the rear end would skid at just 12 km/h. Newer cars with ESP systems perform better, but it is recommended to keep the speed below 15 km/h. The specific slope angle should also be considered; for steep slopes exceeding 8 degrees, it's best to reduce speed to below 10 km/h and use lower gears along with braking to control speed, avoiding prolonged braking that could lead to overheating and failure.
As a veteran driver with ten years of experience, here's some practical advice: don't push for maximum speed when making a downhill U-turn. On regular mountain roads, I usually keep it around 10 km/h, dropping to 5-8 km/h for sharp turns with poor visibility. This is because three risk factors compound: downhill momentum increases stopping distance, centrifugal force pushes the car outward during turns, and the front wheels reach maximum steering angle during U-turns. Once on a southwestern mountain pass, I nearly scraped the cliff wall at 15 km/h in a turn and had to reverse to adjust. Different vehicles behave differently too - long-wheelbase vans need more space than hatchbacks, requiring even lower speeds. The safest approach is to reduce speed to 5 km/h about 50 meters in advance and steer through slowly. If you're going slightly too fast, gently tap the brakes, but never jerk the wheel or brake hard.
