When is a bomb threat serious?
But a bomb threat at Comerica Park during a Tigers' game? No slowing down, no evacuation.
I think when a caller says a bomb will blow up in 10 minutes, you can stop traffic, wait, then do a quick check and resume traffic. It's too easy to make a crank call.
Of course, if it were really my decision, and my job on the line, I might be a tad bit more cautious. It just seems so difficult to set up a bomb on a bridge or in a tunnel, a big enough bomb to damage either, that they would get caught during the installation.