Seattle traffic ground to an eight-hour standstill today after a propane truck overturned on southbound I-5. Both directions of I-5 were closed until the truck had been emptied enough so that it could be righted. The wet winter weather didn’t help, as snow fell in­ter­mit­tent­ly.

Given the danger of a massive explosion, this was the right thing to do. Had the truck gone up, the outcome would have been much, much worse.

Still, it drives home (heh) the fragility of our in­fra­struc­ture. The closure’s effect rippled throughout the region’s roads, causing a systemic failure of the road network. Snarled traffic and chaos everywhere for miles.

We’ve had two similar incidents in recent years, both involving spillages of seafood that caused multi-hour freeway closures. When the system is running hot most of the time, close to its capacity, it only takes one bad accident to trigger cascading traffic jams everywhere.