How to Use Lights Before a Vehicle Enters a Two-Way Tunnel?
1 Answers
All vehicles entering a two-way tunnel should generally turn on their low-beam headlights and avoid using high-beam headlights. If the tunnel itself is unlit, you may switch between lights, but you must switch back to low-beam when approaching an oncoming vehicle. Here are the reasons: 1. The illumination range of low-beam headlights is approximately 30-40 meters. Experiments show that when driving at 55 km/h at night, the braking distance after spotting an obstacle is exactly 30 meters. This means that if an obstacle is detected within the low-beam's range and braking is applied immediately, the vehicle will stop right before the obstacle. 2. Although low-beam headlights have an illumination range of about 30 meters, they feature a distinct beam cut-off line. Most vehicle low-beam headlights measure 30-40 meters in illumination, with the beam cut-off line appearing at around 12-18 meters. The area in front of the cut-off line is brightly lit, allowing clear visibility of objects, and a clearly visible 2-3 meter diameter illuminated area on the ground. The area from the cut-off line to 30-40 meters relies mainly on ground-reflected light. This area can distinguish brightly colored objects but may not easily detect stationary dark-toned objects on the road.
