AT's bus-routes have codes. Why? Because they have designed their systems round them, particularly their website.
But what do people want to know? They want to know how to get from A to B, from a place with a name to another place with a name. Places have names, not codes. People know the A, because they are standing there. All they want to know is what bus/train/ferry they must catch to get to the B.
So the ideal system, the people system, the real-world system, would be based on the real world and people's place in it. It would therefore be based on a map. That is very easy nowadays, particularly because we have Google's maps to use as a wonderfully detailed foundation.
So you are standing somewhere, the A in question, and you want to get to whatever B is your desire. So the ideal system would display a zoomable map, and would have two red, labelled pointers in a box at the top. The box would say, 'Please drag these pointers to where you want them to be'. One would be labelled 'I am here' and the other 'I want to go here'. You would drag them to where you wanted them (and if you were on a cellphone the first one might suggest where it should be via GPS).
If you were catching a bus,when they were dragged to where you wanted them, a window would pop up showing the front of a bus, with the subtitle: 'You need to catch the bus that shows this in its destination window. The next one will be leaving in nn minutes at hh:nn. The journey will take about nn minutes.'
If you were not near the relevant bus-stop it would show you where you had to walk to get to it, and even what the streets along the way looked like if Google had that data.
If you had to catch a train or ferry the window would show where you would catch it and what would be displayed on the station/terminal screen, again so that you could look for the right thing in the right place.
So you would know where to go and what to look for when you got there, so you could get on board the right vehicle (or vehicles if transfers were needed, which would of course be shown).
No codes would be necessary, because, as already stated, places have names, not codes. Codes are for control-freaks who want to impose themselves on reality, not work with it.
The same images of destination windows would show above the printed timetables in bus-stop shelters and leaflets. Not silly codes; actual bus signs.
In short, AT's system should have been based on chaps and maps, not on pointless codes. AT failed, as always, to base its operation on the real world. And the ratepayers were forced to foot the exorbitant bill.