Reading up on the issue at the Transport Politic, and a few issues need to be brought up.
URBANITY Center running is more 'urban'. It is more pedestrianized and more walkable, because the station on a center-running alignment acts as a pedestrian island, making it easier to cross even very wide streets. 400 South in Salt Lake has THREE lanes on each side the TRAX, but is easier to cross than 500 South, which has only 2 lanes in each direction. The dual left turn lights along 400 South means that one side of the road is frequently empty, making it possible to jaywalk with impunity.
STUCK. Using the curb lanes, their is concern about buses getting stuck behind right-turning cars. It's really a non-issue. Getting stuck behind left-turning cars (for center running) is a far more severe issue, from a traffic engineering point of view. It takes a lot of 'green time' on the signal to turn left, so even a few cars can be a delay, while it takes a LOT of cars turning right to slow a bus. Far more likely in my experience has been cars stuck behind a bus at the light....
Which brings up another point, FAR SIDE STOPS. Bus stops need to be on the far side of the intersection, rather than the near side. I know, near-side stops *seem* to make sense, as buses stopped on the red can board passengers...except that doesn't work. The timing never syncs up, and it forces buses to wait through two cycles of the light. A stopped bus also conflicts with cars trying to turn right.
Worse yet, on streets with right turn lanes, the bus has to pull out of traffic to load passengers...and then merge back in. It's the same issue with BULB OUTS. Bulb-outs suck. Traffic engineers may like them, as
they get the buses out of the way, but the best part of all the BRT's
I've been on (Eugene, Phoenix, Boston) notably lack them.The bus comes to a stop, boards, and rolls on.
Which brings me to the issue of CURB HEIGHT. To aid on 'level floor boarding' (including
Roll-on-Roll-off in Eugene) the curb height is raised. Buses no longer
need to 'kneel' or use lifts to pick up wheel chairs, and everyone
boards faster (walking along the ground being faster than climbing up
stairs). Curitiba used raised platforms for it's famous BRT network, and
they have work out well.
But high curbs do more than that...they also solve the GUTTER problem. People waiting for the bus in the rain getting splashed by spray from the gutter is so common in movies it's almost at trope for 'bad day'. It's actually worse in real life. Even if the bus driver is careful, and rolls up s-l-o-w-e-l-y, he's not going to be flush with the curb. There will be a gap between curb and bus (about a foot) filled with six inches of gutter water. A veritable moat. Me, I just leap it. For little old ladies...the wheelchair lift has to come into play. Which takes FOREVER.
Regarding WHEELCHAIRS....whatever buses Lane County Transit (Eugene) bought for it's BRT...buy those. I thought they were just the new standard for buses, until I rode the Valley Metro (Phoenix) BRT. The bus rolled up, front and rear doors opened, the wheelchair ramp extended onto the platform, *two* wheelchairs rolled on, and into wheelchair slots directly across from the door, locked the wheels on their wheelchairs, and the bus rolled on. You know, like they were normal people. The driver never even got out of his seat. Phoenix...still with the special wheelchair lift, driver assist required.