What is the purpose of a license plate lamp?

The purpose of a license plate lamp is to enhance visibility of the license plate at night. This function is essential for law enforcement and for other drivers to clearly see and read the license plate, especially in low-light conditions. Proper visibility of the license plate ensures that vehicles can be identified clearly, which is important for various reasons including safety, accountability, and adherence to vehicle registration laws.

Other options do not align with the specific function of the license plate lamp. The indication of tire pressure is related to vehicle safety systems, dashboard illumination pertains to the vehicle's internal lighting, and lighting for passenger seats serves a completely different purpose altogether. The license plate lamp’s primary role is tied directly to ensuring that the vehicle's identifying information is visible and compliant with regulatory requirements regarding registration equipment.