Traffic **signals** can be **illuminated**, especially at night, to improve their visibility and ensure road safety. This is particularly important for **warning and regulatory signs**, as they help drivers identify risk situations and follow traffic rules properly.

- **Delineation signs** use lights to highlight roadworks and obstacles on the road. For example, **fixed red lights** indicate that the road is closed to traffic, while **yellow lights** prohibit passage through certain areas.

- **Circular traffic lights for vehicles** are also a type of illuminated signal. They use different light colors (red, yellow, green) to regulate the passage of vehicles at intersections and crossings. These lights are essential to maintain traffic flow and prevent accidents.


- Additionally, **square traffic lights for vehicles or lane signals** use lights in the form of arrows or crosses to indicate to drivers whether they can or cannot drive in a specific lane. These signals are crucial for managing traffic on roads with multiple lanes.


Therefore, the illumination of warning and regulatory signs is essential to ensure that drivers can see them clearly, especially in low-light conditions, such as at night.