A properly adjusted mirror allows the rider to see:

A properly adjusted mirror should indeed provide the rider with a view of the lanes beside and behind them. This arrangement is vital for safety as it enhances the rider's awareness of their surroundings, allowing them to monitor traffic conditions on the sides and rear. Being able to see other vehicles in adjacent lanes helps to make informed decisions when changing lanes or maneuvering through traffic, which is critical in ensuring a safe riding experience.

Additionally, it's important for motorcyclists to have a comprehensive perspective of their environment, as motorcycles are smaller and less visible than larger vehicles. This means that adjustment and positioning of mirrors need to be optimal to minimize blind spots. Therefore, choosing mirrors that allow for a broader view rather than focusing narrowly on what's directly in front or only a specific lane contributes to overall safety on the road.