Mark sez in the comments tail,
That same Bay Traffic Center you referenced has photos up of a ship colliding with one of the Bay Bridge’s towers, in the early seventies.
So accidents are hardly unheard of.
Schwarzennegger’s point when he vetoed the bill was that collisions were nothing to worry about because nothing had happened recently.
In fact, the fact that nothing had happened recently was more due to sheer luck than anything else. There’d been something like twenty “accidents” involving tankers carrying “stuff” in the ten years before Schwarzenegger vetoed the bill.
None of those accidents, though, had resulted in a smashup with a bridge or a spill into the bay. Schwarzenneger said the probability of anything bad happening was low. Proponents for SB1480 said ‘it only takes one.’
Spent far too long looking for pictures of ships hitting the Bay Bridge and couldn’t find any.
Did find this blog post and set of pictures of the Bay Bridge at the blog of a world-famous blogger and also found this excellent article in the Chron on the bar pilots written by Kenneth Howe.
I am in awe of the folks who maneuver the shipping traffic into and out of the bay.