Amazing redditer bob_newman posted this great tip in /r/Vancouver:
So I'm sure you've had to deal with those annoying doors that won't open, no matter how hard you push them. Then you have to yell "back door" to the driver. We've all been there. What if I told you that you don't even need to touch the doors at all?
I've known about this trick for a while, yet I've never seen anybody do it. Those doors aren't touch-activated, there are actually a couple motion sensors above the door. They're those white circles under the green light. Just wave your hand under the circles and the doors will open. The only time they won't open is when the green light doesn't come on, in which case you'll have to let the driver know.
Spread the word!
Most of my busing around Vancouver has been in the old style press-this-bar-to-open buses. Great to hear that I can avoid being the socially awkward penguin when I run into one of the newer ones.