Roads for busses are far more expensive to maintain than light rail. Road maintenance of asphalt road for heavy use (like bus lanes) is so expensive that all the bus stations here are using the same road-building techniques the romans already used, and they still go through the stones in a few decades.<p>Just for my city the estimated savings are in the amount of 19 million EUR for switching the main bus lines to light rail.<p>And it would improve quality.