From Saturday, motorists who enter the Yangtze River Tunnel without their headlights on will be fined 200 yuan (US$29), Shanghai traffic police said on Friday.

A police camera located inside the tunnel can spot offenders automatically and send notifications to police, who will hand out punishments later.

Shanghai traffic police

Shanghai traffic police

The specific offense is “ignoring warning signs,” as signs reminding motorists to turn on their lights in the tunnel are now placed at entrances.

Shanghai traffic police

Police said they have been experimenting with the camera since May this year, and offenders received SMS messages from the police with reminders.

The darker environment inside a tunnel can cause momentary blindness to motorists when they enter or emerge from the tunnel, which could lead to traffic accidents, police warned.

The Yangtze River Tunnel links up urban Shanghai and Chongming Island.