What does a solid yellow line on the road indicate?

A solid yellow line on the road serves as a clear indication that passing is not allowed. This marking is used to denote areas where it is unsafe for drivers to cross over into the opposing lane to overtake another vehicle. The intention behind this traffic control measure is to enhance road safety, especially in areas where visibility is limited or when approaching intersections. Strong adherence to these lines helps to reduce accidents and maintain a smoother flow of traffic.

The other options present alternative interpretations concerning road markings that can be misleading. For instance, a line that allows passing would typically be represented by a broken yellow line; bike lanes or speed limit signs have their own specific markings and signage, which do not relate directly to solid yellow lines. Understanding these distinctions is key to navigating roadways safely and in accordance with traffic regulations.