Grouping service numbers by service type, then by area in which they serve.
01-199 Regular routes
31-33 are services operating in Aurora
50-58 all service The northern area of York
in Durham, this can also easily be broken up by the municipality
200-299 Shuttle Services
In Durham, these could be easily wind up being late night shuttles and/or On Demand Services
300-399 Express Services
In Durham, if they ever decided to operate express routes ever again
400-499 School Routes
Don't think this will happen here
500-599 Community Services
Our community busses could go here
600-699 BRT Services (Numbers internal only)
700< Special Services
Canada Day Shuttles?
Soooo... while stealing York's route numbering outline is not at all completely practical, I think that if Durham were ever to completely change numbering strategies, that York's would be a good model outline.