The maximum speed limit for small vehicles on the entire Li-Ning Expressway is 100km/h. The reasons for the 120km/h speed limit on expressways are as follows: 1. Road factors: The 120km/h limit is set based on China's road design standards. The friction coefficient of the road surface, the strength of guardrails, lane width, slope, curvature radius, and sign size are all designed according to the 120km/h standard. If the speed limit is increased recklessly, all related designs would need to be revised, and existing expressways would face reconstruction, which would be extremely costly. 2. Driver factors: The driver's vision, field of view, and reaction time are the three most important factors affecting traffic safety. Generally, as speed increases, a person's field of view and vision decrease. 3. Vehicle factors: Vehicles can run at 120km/h without any issues. In the event of a tire blowout at this speed, there is still a chance of survival. However, at 200km/h, the chance of survival is virtually zero. 4. Environmental factors: Environmental factors include multiple aspects, such as adverse weather conditions, poor road conditions, a mix of vehicle types, overall poor vehicle condition, speeding, fatigue driving, and overloaded transportation. When adverse weather conditions like rain, snow, fog, or ice occur, the safety coefficient of road traffic significantly decreases, requiring drivers to actively reduce speed to ensure safety.
