To **signal construction zones** on the road, it is important to use **light beacons** during **night hours**. This is because, at night, visibility is reduced and the lights help to highlight the construction and obstacles on the road, ensuring that drivers can clearly see the work areas and follow the appropriate indications.

- **Fixed or flashing yellow lights** are used to prohibit passage through the space between them, which is crucial to avoid accidents in construction zones during the night.

- Additionally, **special vehicles** working on the road must carry a **yellow light on** while performing their tasks. This is especially important on highways and expressways, where the light must be on from the time they enter until they reach their destination, to alert other drivers of their presence.

Therefore, the use of light beacons at night is essential for safety in construction zones.