Why are there so many warning piles installed on the expressway, and why not install all the isolation barriers?

The purpose of setting warning piles on expressways is to improve the safety performance of road sections, increase the alertness of drivers, guide vehicles more effectively, remind vehicles to obey traffic rules and avoid accidents, especially in low visibility conditions such as night, foggy days and snowy days. The purpose of setting up isolation guardrail is to prevent vehicles from rushing out of the driveway due to out-of-control reasons, protect pedestrians and buildings around the road, and reduce casualties and property losses caused by accidents. However, due to the need to rebuild road sections, it requires certain investment and time cost, and different types of vehicles, such as trucks and buses on expressways, and different road sections, such as mountainous areas and coastal areas, need to be considered when setting up, so not all road sections can be equipped with isolation guardrails. Therefore, setting warning piles and isolation guardrails at the same time on the expressway can improve the safety performance of this section more comprehensively, ensure the safety of vehicles and pedestrians, and also reduce the occurrence of accidents and the expansion of risks.