The above World Bank table is accurate for the type of roads into Bath, but is optimistic for buses and trams, however it does show that trams are much more effective than buses. More realistic figures are shown in the table below.
Note: In the above Triptych, each of the pictures has the same fixed number of people, very spread out in the cars, condensed in the tram.
Expert comments from below David Walmsley, BSc PhD CMILT MCIHT, Transport Analyst:
TABLE 3.2 MODAL CHARACTERISTICS COMPARED
Mode Characteristics Max. capacity (pphpd)
Maximum Bus Priority 4000
Segregated Busway 6000
The roads into Bath have a maximum carrying capacity of about 1,000 persons per hour. From the information below we can see that buses can be 2.5 times more effective as car but trams are 12 times as effective as cars, and about 5 times as effective as buses.
This is why trams can afford to operate at a 6 – 8 minute schedule throughout the day whereas buses have an inherently longer service interval and are more expensive per passenger kilometre, and thus tend to “cherry pick” the the peak time routes.
“These tables are from “What light rail can do for cities,” published by the Passenger Transport Executive Group in 2005 (now called the Urban Transport Group). It’s a pretty comprehensive guide to trams. You can access it on-line at http://www.urbantransportg
roup.org/system/files/general- docs/WhatLightRailCanDoforCiti esMainText_0218.pdf
These are values for vehicles in ordinary urban service. Table 3.1 gives maximum capacities based on a 1-minute headway, showing articulated buses at 7500 and trams at 21,000, but those are not sustainable except in special circumstances.
From David Walmsley, BSc PhD CMILT MCIHT, Transport Analyst:
In the above, it is showing that the three car tram, white, in the centre, can replace 7 buses, and all the cars on the left, ie an 8 lane highway