Bus lanes still seem like the thing people who hate cars propose to intentionally screw over the people who have them. "Hey, we have this road with two or three lanes in each direction but it's fairly congested. Each of the lanes is carrying something like 50 cars per minute during the day! Why don't we impound one of them so we can have a bus carrying 40 people drive on it once every 15 minutes?"
If you have enough density to justify a bus lane, you have enough density to justify a subway.
If you have enough density to justify a bus lane, you have enough density to justify a subway.