What is a side marker light?

A side marker light is typically a small rectangular or circular light located on the side of a vehicle, usually near the front and rear corners, that indicates the length and width of the vehicle. It is designed to increase visibility of the vehicle at night or in low-light conditions, making it easier for other drivers on the road to see and avoid the vehicle. Side marker lights are typically amber or red in color, and are required by law in most countries. They may also have reflective surfaces to increase their visibility. Some newer vehicles may use LED lights for side markers, which are brighter and more energy-efficient than traditional light bulbs.