Number of Buses per 1,000 People
The number of buses required per 1,000 population will depend on the public transport mode share, the presence or otherwise of rail or other public transport modes, the capacity of the buses, the extent to which they may be utilized in terms of daily kilometers per bus, and the daily number and average length of bus journeys undertaken by each inhabitant of the city.

With so many variables the minimum requirement varies considerably from city to city, but will typically lie between 0.5 and 1.2 per 1,000 population.