The engineers trying to puzzle out the collapse of the I-35W bridge are at this moment pouring out libations of latte to the gods for the video from one security camera that happened to pick up part of the bridge as it went in the river. Seeing something like this happen, even on such a low-resolution record, is worth a zillion of picking through the wreckage, not just for purposes of assigning blame but more importantly for better, safer bridge services in the future.
A video camera to record, say, two hours of video in a loop is now trivially cheap, as evidenced by the thousands we’re putting on lampposts to watch for crime and terrorists in the streets and throughout stores and parking lots. Shouldn’t every structure of any size have a camera or two as a standard accessory, watching it from a well-chosen rather than accidental point of view, so we can learn from the one in thousands that have an informative episode? These don’t even raise privacy concerns; we don’t need to read license plates to understand a bridge collapse.
And on the same principle, shouldn’t every airliner have three (these are called lipstick cameras because that’s about how big they are) high on the rudder, looking at each elevator and forward at the rest of the plane, recording into the black box data recorder?