When is it illegal to pass another vehicle?

Answer: A — When there is a solid yellow line on your side of the road

It is illegal to pass another vehicle when there is a solid yellow line on your side of the road because this line indicates that passing is not allowed in that area. The solid yellow line serves as a visual warning to drivers that it is unsafe to overtake another vehicle due to factors such as limited visibility, curves, or other hazards. The intention behind this regulation is to promote safety on the road, as passing in such areas can lead to head-on collisions or other serious accidents. The other scenarios presented do not inherently signal that passing is illegal. A dashed white line, for example, indicates that changing lanes or passing is permitted. Changes in speed limits and the act of driving downhill do not, by themselves, dictate the legality of passing another vehicle, as those situations depend more on road conditions and traffic laws rather than a specific marking or situation.