A bus that gets stuck in traffic is by definition a failure. It will (again by definition) never be a viable alternative to driving, meaning a reinforcing loop where more driving means more traffic for the bus to be stuck on, meaning the bus is even slower and less attractive...
Bus lanes make a bus a very good alternative to driving, and they are much more efficient space-wise compared to cars (and god forbid, pick-up trucks), which means you can get more throughput...
> It will (again by definition) never be a viable alternative to driving
I don’t follow the logic here. Why would a bus (periodically) getting stuck in traffic forever invalidate it in comparison to getting stuck in the same traffic in a car?