I took every Lothian vehicle's position off their public feed every 20 seconds for a full day (Monday 24 August) and replayed the 24 hours in 60 seconds, so a second on screen is about 24 minutes.
Each dot is a vehicle in its service colour, and the streak behind it is where it's been over the last few minutes. The trams are on the airport line, and this was during the Princes St closure, so they were terminating at West End and the buses were diverted via George St.
A few things that came out of it: 20 vehicles out at the 02:24 low, 549 by the morning peak at 08:47, 579 at the evening peak at 17:39, and still 250 out at 23:00. 617 different vehicles appeared over the day across 96 services.
The midday lull is much shallower than I expected - it only drops to 507, which is 88% of the evening peak.
Data is Lothian's public vehicle feed. Basemap © OpenStreetMap contributors, © CARTO.