The capacity of a bus is an important factor influencing both environmental impact and the economy for the operator. In rush hours buses are essentially full in the direction from living districts to the office districts and almost empty in the opposite direction. This is the nature of most public transports for commuting.
In the rush hours it is most important to meet the capacity demand. In the example below I have studied 459 bus routs in London (UK) during the rush hours.
The table should be read like this:
Two bus routes have four buses per hour, arriving every 15 minutes.
Nine bus routes, or five buses or less per hour, arriving less frequently than every 12 minutes, this summarise to 2% of the routs and 1% of the buses. etc.
If the bus arrives at least as often as every 10 minutes people tend to accept the average wait of 5 minutes. In London in the rush hours 98% of the bus routes and 99% of the buses arrive at least as often as every 10 minutes.
The capacity of the bus is thus of importance for 99% of the buses, else there is not much need for increasing the frequency.
The limiting factor for the bus capacity is mostly the total weight of the bus. A standard 4×2, 12m bus inEurope is mostly registered to a total maximum weight of 18 tonnes, this goes for both double deckers and single deckers.
Other factors influencing the transport capacity is:
1, Time spent at bus stops: The stop time is mainly limited by the boarding time, and time for driver to attend passengers, for example if ticketing is on-board. To shorten the boarding time, broad fast opening doors are of importance.
2, Average speed: The average drive speed is mainly restricted by the maximum speed and disturbance of other means of traffic. The latter can be solved by priority at junctions and dedicated infra structure realised by separate lanes, bridges and tunnels.