In which conditions may legal maximum weights not be safe?

The correct answer highlights that during bad weather in mountainous areas, legal maximum weights may not be safe due to various safety concerns. When weather conditions deteriorate, such as heavy rain, snow, or ice, the risk of losing traction increases significantly, especially on steep inclines and declines. In mountainous regions where roads can be winding and narrow, the added weight from legal maximum loads can make it more difficult to control the vehicle, potentially leading to accidents or rollovers. Additionally, heavy vehicles require longer stopping distances, and in adverse conditions, drivers may find it challenging to stop in time to avoid hazards.

In contrast, sunny weather typically provides optimal driving conditions, making it safer to operate vehicles up to their legal maximum weights. Flat terrain also offers favorable driving conditions with less risk of loss of control, and urban settings may allow for well-maintained roads but pose their own risks due to traffic congestion, which differ from those encountered in mountainous areas.