Catching up on the dual door discussion, my experience is that often on the m1, the 2nd door isn't properly used, which negates having it.
By this I mean that, particularly at busy stops, there are some drivers who won't open the front door for boarders until everyone who wants to has alighted. So having two doors in those circumstances becomes unnecessary.
The same can be said from my experiences on the Bath uni services. On the regular ADL examples, the typical passenger behaviour is to alight from the rear doors only if you're sat downstairs at the back, the front doors usually being used by everyone lighting from upstairs. This can add somewhat to the dwell times, especially at the stops in Oldfield Park. In some cases, the drivers either shut the rear doors after everyone downstairs has got off, or even don't bother using them at all!
However, when Scanias are used, I find that many more people use the rear doors, particularly coming down from the upper deck. This is down to a combination of the rear doors being one window further forward & the metrobus signage instructing passengers to alight through them still being in place.
Lastly, the rear doors are more frequently used on the artics, for obvious reasons. There have still been countless occasions where drivers forget to open the rear door, even though a quick glance at the CCTV would reveal someone standing by them. One occasion even saw a driver not only fail to open the rear door, but also subsequently ignore the frantic bell pushes from the back and drive on, then giving the passengers in question a bunch of excuses and no apology when confronted! Rather unacceptable..
