Abstract: A method and a device for controlling traffic flows with vehicles transporting hazardous goods, the vehicles moving through a security-critical traffic area of a road network, in particular through a road tunnel. When a vehicle approaches the traffic area it is established whether it is a vehicle transporting hazardous goods, and a traffic signal is output to the vehicle approaching the traffic area. In that a digital image is recorded of a vehicle approaching the traffic area, and in that the recorded image is digitally analyzed to recognize a feature which identifies a vehicle transporting hazardous goods, vehicles transporting hazardous goods may be recognized and controlled simply, reliably, and largely independently of vehicle equipment.