Where should a mirror be installed on a motor vehicle?

A mirror should be installed on the left outside of a motor vehicle because this position provides the driver with the best view of traffic coming from behind on the left side, which is crucial for safe lane changes and merging. The left outside mirror allows the driver to monitor the position of vehicles in adjacent lanes, facilitating better decision-making on the road.

While the inside mirror is essential for rear visibility, it does not replace the need for outside mirrors, especially for blind spots and wider field of view. Having the left outside mirror assists in enhancing the driver's awareness of the surroundings, thus promoting safer driving practices. Positioning a mirror on the dashboard is impractical as it would not provide effective rear visibility.