Bus, tram or train?

This table is from a report produced by the Commission for Integrated Transport in 2005. The figures give maximum system capacity (passengers per hour per direction). It suggests that when there are more than about 3,000 passengers per hour - say around 40 buses - it is time to start thinking about replacing them with trams.

Standard bus	2,500-4,000
Busway	4,000-6,000
Guided bus	4,000-6,000
Tram/Light rail	12,000-18,000
Heavy rail	10,000-30,000

Link to full report