Because so many metropolitan areas are seeing the proliferation of personal automobiles result in dangerous levels of ozone and other health-threatening air pollutants, transit should seek to minimize its own contribution to the problems it is asked to solve. Electricity is the best fuel for this need because its generation is centralized, making pollution control more manageable. Few people realize that, in addition to air pollution, the automobile/road combination leads to other forms of pollution as well. Large roads form water shed problems during rain storms, causing soil erosion. Oil dripped from imperfectly maintained engines drains into the soil from the roadways. And, few engines operate quietly. When hundreds of engines are placed together on a roadway, the cumulative noise level can be substantial. Neighborhoods which once were in a quiet area find themselves enduring constant noise when a new major road is built nearby. Transit, if expected to reduce the need for building those new roads, must be quiet in operation and friendly to the environment.