Sure you can check the lights, make observation checks on the tyres, observe if any of the warning lights on the dash are lit but what else? As a driver this is all you could reasonably do.
OK, bear with me as it was an early start so from memory, my first use check routine is:
Check I've got the right vehicle. This is important. Board; make sure Parking Brake is applied and vehicle in Neutral.
I'd advise you to wear a good head torch. It is 04:15 and it's almost winter!
Switch on Battery Isolator (Kill switch) Ignition on, observe Self Check (Like Pre-heat on some vehicles)
Clean Touch Points.
Start engine and wait for Air Pressure Gauges to reach their normal values. Air holds the Parking Brake off, so no air= no forward movement!
Switch on all lights; internal and external- remembering the Destination Blind Lights too! Set up Electronic Ticket Machine, Check the Mobile Data Terminal can make announcements via the Public Address System.
Set Destination Blind to relevant route (if electric)
Check Windscreen Wipers, washers assault alarm and horn.
Make sure both sets of doors are closed. Check surroundings- and therefore external and internal mirror settings before deployment of Wheelchair Ramp.
Once 'ramp is deployed, open and close both sets of doors from the cab controls then retract ramp.
Take the opportunity to check the cab door Covid-19 seals as stepping carefully out of the cab.
(at this point, I take the opportunity to clean various buttons and handles as I go with sanitary wipes)
Open the front doors using the emergency buttons and close on the way out.
Now we'll start our walk round check at the front of the vehicle.
Using the accepted "Top Middle Bottom" routine, we start at the top, checking the Marker Lamps, Destination Display and Back-lights, Glass and rubbers
, Windscreen* wipers, Dash Bumpers and Number Plates. We're checking for obvious damage; sharp edges cracks* and chips* in the driver's field of vision.
All ok, we move to the R/H side of the bus. Again, Top Middle Bottom (TMB) and again checking bodywork and glass for serious damage, sharp edges and making sure all hatches doors and panels are secure.
We'll be listening out for air leaks throughout as reservoirs are fitted in various locations. You'd know where these are from Type Training.
We will visually check the tyres for cuts to the cords, bulges tread depth (minimum 1mm across three quarters of the width and around the full circumference. Yes, it is less than the 1.6mm for cars)
We will also check the wheel discs for damage, cracks and the wheel fixings for security. Most buses have those brightly coloured check links which show movement of the wheelnuts by pointing in a certain direction or bending.
If not fitted, check for Rust Bleed which might indicate a wheelnut has been loosened and moving around.
Move towards the rear of the vehicle (TMB) check side marker lamps if fitted, get to the rear wheels.
Twin wheels, so if the outer tyre looks low, grab an Engineer as the inner wheel might be flat. Check the rear hub for Oil Leaks.
Open the Emergency Exit all the way from the outside, check Diesel and Adblue Filler caps are closed and not leaking.
Rear of the bus now. Again, TMB, usual checks now, and we'll check carefully for Oil and Fuel Leaks by crouching down and looking under the rear of the bus. Sometimes it is easier to move forwards a bit to check for this. Obviously any excessive smoke will be noted. This is highly unlikely.
Check Emergency Exit operation if tall enough!
Carry on checking the L/H side but we're going to press the Damp Request button, open the Centre Doors from the outside, step inside and close the door from the button and check the Sensitive Edges of the doors. The doors will open immediately on sensing an obstruction.
Step out carefully and continue TMB checks, obviously repeating checks to wheels, fixings, etc as you go.
Now you are at the front door. You'll notice that they're closed; you did this so you can check the external button...
Get into the cab and close the centre doors. Now for ease of writing, we're checking a single decker. You are going to check the interior for sharp edges, security of panels and grab rails, cleanliness, operation of Bell pushes, lighting displays, graffiti, and the emergency centre door buttons as well as the operation of the emergency exits windows and for air and water leaks. You'll check the Fire Extinguisher is fitted and check the pointer is in the correct portion of the gauge.
All done? Not quite. We'll need a glamorous assistant to stand behind the vehicle and assist with checking the reversing lamps and brake lamps.
You're ready to go!
Oh. And to do all that, you have ten minutes. I always take longer to the chagrin of some Controllers.
This is not an exhaustive list. Some buses will vary. I'd find it easier to show people to be honest. It was my bread and butter as a Bus Driving Instructor a few years ago.
Hope that provides some insight!