I wouldn't recommend a friction drive if you need to ride in the rain.
My experience is that even water running across the road will cause
the roller to spin.
If you have to you can ride in the rain by feathering the throttle and
pedal assisting a lot but it really isn't much fun....
The new Staton friction roller design may work better than the old
knurled one but personally I wouldn't want to rely on a FD in Chicago
for daily transportation.