I think this is the correct pair of words. I like known headways. What I take it to mean is that a public transport vehicle will run at certain predictable intervals.
An example would be when we lived in Balaclava and often used the train. I knew that in the AM peak, the train was every ten minutes and ran on the hour, so 8.00, 8.10, 8.20, 8.30 etc.
Later in the day when the fifteen minute service started, it was .03, .18, .33, 48. This went on until the afternoon peak service started.
I also knew that it was a thirteen minute trip to the city, and so I could also roughly calculate what time the train would be at other stations if needed to travel from them. I knew these times in bothe directions, for both peaks and day time services and weekend daytime services. I rarely needed a timetable.
The day service is the same, but the AM service has changed and it no longer has known headways.
From 6.47AM the gaps are, 14 mins, 13, 13, 11, 10, 9, 9, 8, 10, 9, 10, 8, and 9, where we reach 9.00AM.
The same goes for trams. I used to be a regular user of the now re-numbered route 69. At Balaclava Railway Station, the trams were evenly spaced. Now look at the AM peak.
8 mins, 8, 9, 10, 10, 15, 16, 15, 10, 14 etc.
It is clear to me that in the past, the service was matched to a timetable. Surely a good thing. Now, the service is matched to......well I don't what, possibly $$$.
Do feel free to point out why it may be a good thing and that there is some benefit to the travelling public.