The sign "Announcement or continuation of the detour here left implementation according to RUB if necessary with numbering" indicates that there is a detour route that cyclists should follow if necessary. Specifically, this sign informs road users that the usual path is obstructed, and they must divert left to follow the designated detour route.

In general, detour signs are used to guide drivers and cyclists around construction sites, road closures, or other hazards. It is essential to pay attention to these signs to ensure safety and compliance with traffic regulations. Failing to follow detour signs can lead to hazards and potential penalties. Always look for additional signage or instructions that might be provided for guidance on the detour.