What does 'except shuttle buses' mean?

[VanCarmen]

In urban public transportation, a shuttle bus refers to a vehicle that operates only on a partial segment of a full bus route to meet passenger demand. Operating shuttle buses can satisfy the travel needs of passengers on high-demand segments when the route capacity is tight and accelerate vehicle turnover. 1. Purpose: To accelerate vehicle turnover 2. Characteristics: Fewer departures compared to regular routes 3. Two types of shuttle buses: The first type is when the regular route follows A-B-C-D, while the shuttle route follows A-B-E-F. This means the starting station and some stops are the same (A-B points), but the latter stops and terminal station differ. The regular route stops at C-D points, while the shuttle stops at E-F points. The second type is when the regular route follows A-B-C-D, while the shuttle route follows A-E-F-D. Here, the starting and terminal stops are the same (A-D points), but the intermediate stops differ. The regular route stops at B-C points, while the shuttle stops at E-F points. Shuttle buses have fewer departures compared to regular routes, some even equivalent to scheduled buses.