Worst of all, even though a bus is a much more efficient use of crowded space than a private car, it ends up stuck in the same traffic jam as everyone else.
The best light rail systems avoid these pitfalls, giving trains dedicated lanes, a sensible way for customers to pay, and stations that are far enough apart that the train isn’t stopping every three blocks. But low-quality rail can have the exact same problems. ... But by the same token, it should be perfectly possible to construct bus lines that have the major virtues of light rail and just happen to run on roads rather than rails. ...
But the biggest possibility for bus transit wins requires something even more contentious than spending money—repurposing lanes. ... Far and away the cheapest way to speed the movement of people through congested space is to take some of those lanes away from cars and give them to buses. That will decrease your movement of vehicles, but increase your movement of people since buses are a much more efficient use of space.
--Matthew Yglesias, Slate, on saying no to light rail