Green Wave Traffic Light Pre-emption is “…usually not done for trams…” ie not buses (Says World Bank)

The World Bank discusses traffic light priority systems here:  https://www.ssatp.org/sites/ssatp/files/publications/Toolkits/ITS%20Toolkit%20content/its-applications/traffic-management/traffic-signal-priority.html

Extract:from above

  • In some cases, public transport vehicles may be given ‘zero wait’ priority – this is usually only done for trams, but may also done for BRT. In this case, the phases are extended or truncated sufficiently quickly that the light is always green when the vehicle arrives.

The reason for this is, that to carry the same number of passengers, as a tram, 4 – 5 times as many individual bus movements would need to be accommodated, and these would create far to many self-defeating pre-emptions.