What is the purpose of the dotted line on the rearview mirror?

[Paul]

The dotted line on the rearview mirror is primarily used to observe situations at a farther distance on the side of the vehicle. Inside the dotted line, the curvature radius is larger, used to observe situations at a closer distance on the side of the vehicle. The combination of these two curvatures helps minimize blind spots in the rearview mirror. The smaller area of the dual-curvature rearview mirror may also feature a small indicator, which functions as a "side blind spot warning system." When there is a potential collision risk on the side of the vehicle, this indicator will flash to alert the driver. If the body of the following vehicle has entered the dangerous area to the left of the dotted line on the rearview mirror, it indicates that the following vehicle is very close to your car, and you should not change lanes at this time. If the left side of the following vehicle's body is close to the boundary between the safe zone and the danger zone, you should be extra cautious, but signaling and changing lanes at this time is still safe. If the following vehicle is in the safe zone, located in the center of the rearview mirror, it means the following vehicle is 15-20 meters away from your car, and you can proceed with normal lane-changing operations. Functions of the dotted-line rearview mirror: A rearview mirror with a dotted line is known as a dual-curvature rearview mirror. Divided by the dotted line, the mirror is mainly split into two parts. The dotted line is located on the outer third of the mirror, with the inner area being the normal reflection zone, also referred to as the standard rearview mirror area. The viewed area here is essentially 1:1, with minimal distortion. The outer area has a greater curvature, providing a wider field of view due to its larger curvature, which helps drivers better adjust their vehicle's position. For example, during reversing, the wider curvature allows for a broader view of the reversing area. The entire dual-curvature rearview mirror acts like a small convex mirror, offering the driver a wider field of vision. Because dual-curvature rearview mirrors are generally smaller in size, they can effectively reduce wind resistance and lower the vehicle's fuel consumption. The warning device on the dual-curvature rearview mirror alerts the driver when there is a potential danger on the side of the moving vehicle, prompting the driver to take evasive action. Most vehicles also come with a rearview mirror heating function. In special weather conditions, activating the heating function can prevent fogging on the rearview mirror, ensuring clear visibility for the driver. During heavy rain, applying a rain repellent to the rearview mirror can help. This repellent forms a thin film on the glass surface, allowing water droplets to slide off quickly. Rain repellent can also be used on the windshield. It's important to avoid scratching the rearview mirror, as the outer shell is plastic and difficult to repaint if scratched. When parking on the roadside, it's advisable to fold the rearview mirrors.