The rearview mirror in vehicles is designed to provide a clear view of the area behind the vehicle. When it comes to determining which rearview mirror is for left and right, it is crucial to understand that the mirrors are not inherently designed for a specific side. However, the placement and orientation of the mirrors can help drivers determine their purpose. Typically, the driver's side mirror is mounted on the left side of the vehicle, while the passenger side mirror is mounted on the right side. This arrangement is standard in the United States and many other countries due to the widespread use of right-hand drive vehicles. The driver's side mirror is designed to provide a wider field of view to the driver, which is essential for safe maneuvering and reversing. Conversely, the passenger side mirror is typically smaller and offers a more focused view of the side of the vehicle. This distinction is important for several reasons.

Firstly, the driver's side mirror is larger to accommodate the wider field of view required for the driver. This larger mirror allows the driver to see more of the area behind and to the sides of the vehicle, which is crucial for safe driving. According to the National Highway Traffic Safety Administration (NHTSA), rearview mirrors are a critical safety feature that helps drivers avoid collisions. The NHTSA reports that rearview mirrors can reduce the risk of rear-end collisions by providing drivers with a clear view of the area behind their vehicle.

Secondly, the passenger side mirror is typically smaller and offers a more focused view of the side of the vehicle. This is important for the passenger, who may need to monitor the vehicle's blind spots or check for other vehicles approaching from the side. The passenger side mirror is also designed to provide a view of the vehicle's exterior, which can be useful for checking the vehicle's appearance or for signaling to other drivers.

In addition to the size and orientation of the mirrors, the convexity of the mirrors also plays a role in determining their purpose. Convex mirrors are curved outward and provide a wider field of view, making them ideal for the driver's side. Concave mirrors, on the other hand, are curved inward and provide a narrower field of view, which is suitable for the passenger side. This distinction is important because convex mirrors help the driver see more of the area behind the vehicle, while concave mirrors help the passenger monitor the vehicle's sides.

In conclusion, the rearview mirrors in vehicles are not inherently designed for left or right, but their placement and orientation are determined by the standard configuration of right-hand drive vehicles. The driver's side mirror is typically larger and convex, providing a wider field of view for the driver. The passenger side mirror is smaller and concave, offering a more focused view of the vehicle's sides. This distinction is important for safety and convenience, as it allows drivers and passengers to monitor their surroundings effectively. According to the NHTSA, rearview mirrors are a critical safety feature that can help reduce the risk of collisions.