What minimum distance should you keep from the vehicle in front of you when you get stucked in a traffic jam in a tunnel?

In accordance with the Road Traffic Act, in the event of a stoppage in a tunnel resulting from traffic conditions, such as the traffic jam shown in the picture, the driver is required to keep a distance of not less than 5 metres from the preceding vehicle. This regulation is intended to ensure manoeuvring space and to facilitate access for emergency services in case of an emergency.