ChrisCooper
Established Member
That is a problem with high frequency routes, they rely on very good timekeeping and particularly headway keeping to work and not bunch. Even 10min frequency services can easily bunch. Often it's relying on the disipline and knowledge of passengers (knowing another bus will be only very shortly so not expecting to get on whatever is at the stop when they come into view of the stop), and the brutality of drivers (going when ready and not hanging around for passengers who are approaching). Metros suffer it too, especially when people start trying to force on as the doors close. Buses also suffer due to things like traffic lights, a bus that keeps getting red lights will get caught by one behind that's getting greens. Bus timetabling is very unpredictable and especially at busy times buses arriving anywhere from a few mins early to a few mins late at timing points is common and hard to avoid (as said, how they high traffic lights can add minutes onto the journey if there are multiple sets).
Another problem buses have is that maintaining seperation is much harder. For trains signalling does it automatically to an extent (even on metro system trains will always leave stations a certain time apart due to signal headways, and trains will never overtake under normal circumstances). Trams can suffer from that too unless signalled, although seperation rules for line of site can help and end up working like signalling anyway. Of cource moving block signalling can be as bad as line of site depending on how implemented.
The idea high frequency service though would have services leaving at exact (or within a few seconds) headways, so a 1 min frequency means that one leaves every 1min, not there is a gap then a group come together. The more human involvement though the less likely it is to work, and you need accurate information on the time since the previous departure to even have a hope (easier with trains than buses, but by no means impossible, even with fairly basic technology).
Another problem buses have is that maintaining seperation is much harder. For trains signalling does it automatically to an extent (even on metro system trains will always leave stations a certain time apart due to signal headways, and trains will never overtake under normal circumstances). Trams can suffer from that too unless signalled, although seperation rules for line of site can help and end up working like signalling anyway. Of cource moving block signalling can be as bad as line of site depending on how implemented.
The idea high frequency service though would have services leaving at exact (or within a few seconds) headways, so a 1 min frequency means that one leaves every 1min, not there is a gap then a group come together. The more human involvement though the less likely it is to work, and you need accurate information on the time since the previous departure to even have a hope (easier with trains than buses, but by no means impossible, even with fairly basic technology).