On Jan 14, 1:26*pm, Shaun Eli wrote:
Re the bridge analogy- did they replace the bridge not only to save
lives but also to have a bridge in operation? If an old bridge falls
down not only do people die but you've got to replace the bridge
anyway, and in the years it takes to do that you've got no bridge.

Good point, about bridge availability.

But the probability of the entire bridge failing is small.
Plus California has speciality contractors that excel at putting
bridges & freeways back into service VERY quickly.

You can buy a lot of "down time" for $10 billion.

And you have to factor in the probability of failure over time (ie
probability of failure on a per year basis)

cheers
Bob