If you haven’t already heard, a portion of a freeway interchange in the East Bay was destroyed when an oil tanker truck took a tumble and exploded last weekend. The accident was followed by paranoid fervor, by the press, about how transportation in the Bay Area would come to a complete standstill come Monday morning.
Well, it didn’t happen. Although time could prove a different outcome, it seems that people were able to figure out alternate freeway routes – or took transit – to get to San Francisco and to San Jose from Oakland, and the predicted multi-mile traffic jams just didn’t happen.
The fears associated with this episode occur quite often in transportation practice. It is assumed that people will always make an irrational decision and pile onto the same roadways. However, as has been shown when the Embarcadero and the Central Freeways were torn down in San Francisco, more congestion does not occur – but rather disperses – due to the lack of the centralized congestion nodes that freeways create.
The best way to think about traffic is to think about how water flows. This is why we call it ‘traffic flows’. If you run water through a pipe at high pressure (or cars on a freeway at high speeds) you can move heavy volumes efficiently through a small space. Furthermore, as water after a rain runs through networks of storm drain systems, cars can move through a surface road network or onto other freeways, and achieve the same time efficiencies (as they would on one freeway) if there is enough connectivity within the surface road network.
One interchange in repair for a few months, life goes on…
http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/05/01/MNGQUPIKGM1.DTL
May 1, 2007 at 6:00 pm
You have to give the press some credit rather than faulting them for calling wolf. In other words, by publishing frenzied predictions of traffic meltdowns, reporters actually helped to alert the public to the need for finding transit alternatives.