The conventional wisdom is that projects like the RailRunner and Mayor Marty’s proposed trolley are inherently “green” because they get people out of their cars. While this is usually the case if a bus or train is full and automobiles contain only one passenger, this is not how the equation usually works.
In fact, Brad Templeton does an excellent analysis of various transit systems and compares them with automobiles of different sizes and occupancies and finds that construction of new transit systems and even the use of buses is not necessarily green, especially when compared with small cars and cars containing multiple passengers.
As he points out:
A full bus or trainload of people is more efficient than private cars, sometimes quite a bit more so. But transit systems never consist of nothing but full vehicles. They run most of their day with light loads. The above calculations came from figures citing the average city bus holding 9 passengers, and the average train (light or heavy) holds 22. If that seems low, remember that every packed train at rush hour tends to mean a near empty train returning down the track.
After all, how often do you see empty or out of service buses driving around town? The Rail Runner certainly isn’t always full.
Templeton isn’t the only one who is skeptical of the relative “green-ness” of transit. Randal O’Toole over at the Cato Institute argues in a recent research paper that rail transit doesn’t save energy or reduce greenhouse gas emissions.
Before we embark on massive new transit projects, we should carefully analyze whether or not these projects are really good for the environment.