Different transport modes should not share numbering systems
Friction: E.g. letters for metro, numbers for buses.
Why this matters
“Take the 4” is ambiguous if there is a Bus 4, a Tram 4, and a Metro 4.
Good Sense principle
Assign distinct namespaces to different modes.
- Metro: Letters (A, B, C)
- Tram: T1, T2
- Bus: Numbers (10, 11, 12)
This reduces the need for context (“The 4… bus?”) and makes communication clearer.