Vulnerablilities

The media is abuzz today with discussions about the tanker truck which caught fire and destroyed a bridge in the San Fransisco area. I've seen all sorts of comments ranging the whole gamut, from those that express shock that concrete and steel can collapse under intense heat, to how absolutely vulnerable the entire transporation system is. It's this latter comment which bothers me.

First, a missing overpass isn't a catastrophic failure of the transportation system. It's inconvenient that the commute might take a bit longer (this morning's did not), but hardly a problem. If you take any highway in any major city and close it due to a wreck, and you'll have a nasty traffic problem. That's not a catastrophic failure -- trains (both freight and passenger) can keep running just fine; detours are found for those who drive.

Second, having a network of highways isn't a vulnerability. You either need an overpass, a tunnel (underpass), or an intersection. All of these can be destroyed just as easily I imagine -- the burning truck would have caused a tunnel collapse and likely melted the pavement of an intersection. Though an intersection could be more readily repaired than the other two options, the point is all of them are vulnerable.

Third, heaven forbid people telecommute, carpool, or pay for the bus. Of course, Arnold made today a ride-free day on all public transport, which I personally don't understand. If you encourage everyone to take public transit today, what will they do tomorrow? I see the following options:
1. They take public transport again, paying for it. The question is, why wouldn't they have paid for it today?
2. They don't take public transport because it's not free on Tuesday. They drive to work, causing traffic jams. The question is, what's the use of delaying the traffic jam from Monday to Tuesday?