In case of emergency, the emergency lighting of road tunnel has two main functions: one is to provide guidance and visibility for the driver so that he can drive out of the tunnel; The second is to provide guidance and visibility for pedestrians evacuating the tunnel on foot.
The road tunnel emergency lighting system is powered by an uninterrupted power supply (UPS). In the case of failure of normal power supply, it is recommended that the response time of emergency lighting device should not exceed 0.3s and the maintenance time of emergency lighting should be 30min if there is no special regulation.