The other day I rode my Plus wheelset to work: 26 x 3.0 in the front, 26 x 2.8 in the rear, both on 40mm(internal) rims. The front tire went flat, and I was forced to bus it home. I let the air out of the rear tire as well and both tires were able to fit, with a little coaxing, into the bus rack. Rear tire was tubeless and aired right back up afterwards. Not ideal to have to deflate your tires to use the bus, but, in a pinch, it works.
I'm thinking I should just get to the bus stop early some day with my calipers and measure width of the slot your tire drops into, since the bus usually idles at my stop for about 5 minutes before moving on.
I just realized that on an upcoming trip I will either have to bus my bike out of the airport to downtown or ride about 30 miles. If I were arriving earlier in the day, riding would be fun, but now I'm thinking that bussing will be part of the plan, and I'd better choose my tires accordingly. Or I could just wait until I get off the bus to inflate them, I guess.