This post from MetaFilter describes an awful situation better than I can:

Yesterday in Los Angeles a suicidal local man stabbed himself in the chest, slit his wrists, and drove his car up onto train tracks, lost his nerve and hopped out at the last minute, to watch in anguish as not one but two trains collided with his car and with each other, killing 11 people (so far) and injuring almost 200 others.

The first few replies in the MetaFilter thread make some interesting – and scary – points.