Traffic Light System Diagram - Red Light Active with Control Unit #209185 (License: Personal Use)

This schematic illustration depicts a standard vertical traffic signal with three circular lamps-red on top, yellow in the middle, and green at the bottom-where only the red lamp is lit, signifying a stop command. To the left, a simplified white control box features a black display area and a small red indicator light, suggesting system status or activation feedback. The design uses high-contrast colors for clarity and is typical of instructional or regulatory visual aids.

Used in traffic engineering documentation, driver education materials, road safety websites, and municipal signage guidelines. Matches user intent for understanding signal operations, troubleshooting, or learning traffic control logic.