Transportation network effects

Network effects explain why many systems become exponentially more useful as they are used by more people. Communication systems work that way: fax machines became much more useful as more businesses bought fax machines. Social networks work that way: Facebook became much more useful when the majority of your social contacts joined Facebook. Transportation systems, however, diverge.

Driving around Boston maximized its network effects a long time ago. We reached sufficient usage more than half a century ago to develop a complete system of roads, parking, gas stations, and repair shops. New fueling systems, such as charging stations, present a new network effects challenge: it’s not worth building charging stations everywhere until enough cars need them, and people are hesitant to purchase electric cars without knowing that there will be enough charging stations. But leaving that aside, we are not waiting for sufficient adoption of driving to make driving a better choice. Instead, driving long ago passed the event horizon into capacity saturation problems. When road usage saturates the road capacity, you get traffic congestion, which makes the entire system less useful for everyone instead of more useful. Adding road capacity is very expensive, and urban planners recognize that any new road capacity is immediately saturated as well.

Public transportation around Boston has lots of additional capacity. It is easy to increase the frequency of trains and buses, it is easy to add bus routes, and it is therefore easy to handle far more passengers. And with increased frequency and added bus routes, public transportation becomes more useful to current passengers and attracts new passengers, which can support further expansion. That is the classic network effect.

The trouble is that we put all of our resources into supporting the driving network instead of the public transportation network. This is a huge missed opportunity. And now the MBTA is looking to reduce service by reducing frequency and eliminating bus routes, and raise fares at the same time. If we want to leverage our public dollars, we need to shift our funding from the driving network to the public transportation network, not the other way around. And I say this as a committed driver.