A street can easily handle bikes and public transit if it is well planned. But I also lean towards busses and subways, tramways only where it can be isolated from other traffic.
Also, on busy streets bycicles and scooters should have their own lane. Streets too small for that shouldn't be busy...
Even if you know they are there, they pose a risk for bikers. I once nearly fell when I had to evade a traffic situation which led me directly into the tracks.