Buses

I'm reading a book called, "Energy for Future Presidents" by Berkeley Physics Professor Richard A. Mueller. I thought the following excerpt about buses was relevant, considering so many people complain about lack of Sam Trans service in Pacifica.  Also, some insist that increased bus service would alleviate the need to expand Highway 1, even though the San Mateo County Transportation Authority and Sam Trans have determined that 60 full buses per hour would be required to move traffic through town at the same rate the highway widening would, and therefore ruled it out as being too expensive and unrealistic.

Mueller is writing about efficient energy use rather than traffic congestion, but he offers his idea of when buses work and when they don't -

"Many people take it for granted that increased public transportation is the obvious solution to our overreliance on autos. Buses carry more people per pound than does a car, so you might think they would get more miles per gallon per person. And they would – if buses were always full. Public transportation can save enormous energy when used in crowded urban environments, but ironically, it can waste energy when used in suburbs and countryside.

If buses don't fill up, and if they have to make round-trips during rush hour – empty on return – then they might not save net energy. You can improve efficiency by using smaller buses during the slow hours, but then you run the risk of having to pass by people at some stops. It's hard to win. Moreover, buses make lots of stops and starts – and that frequent acceleration is when fuel efficiency drops enormously. If the bus has to take circuitous routes in order to get close to where passengers live, the passengers wind up traveling greater distances than if they drove their own cars. To get people into the habit of riding buses, buses must be available all during the day without long waits; otherwise people will take their cars. All this means that a lot of the buses spend a lot of time with only a few passengers.

A detailed study of bus transportation in the suburbs around the country done by the Institute of Transportation Studies at Berkeley found that the average break-even point is determined by population density. If there are more than 15 households per acre, then public transportation works. If the population density is lower, then using buses increases energy use. This means that if you live in a suburb with quarter-acre or even one-tenth-acre lots, your community will not save energy by establishing bus routes.

So beware of simplistic solutions such as “more public transportation.” There are often hidden subtleties and unintended consequences."

Posted by Steve Sinai