When are you not allowed to pass another vehicle?

Passing another vehicle is prohibited when you are nearing the top of a hill because visibility is typically reduced in this scenario. When approaching the top of a hill, you cannot see what is on the other side, including potential oncoming traffic or hazards. This significantly increases the risk of a collision if you attempt to overtake. The law is designed to ensure the safety of all road users, emphasizing that areas with limited visibility, such as hills, are not safe for overtaking. Therefore, it is crucial to exercise caution and refrain from passing in these situations to prevent accidents.