Adena blogged the AP story about the response of mapping sites in re-routing around the Bay Area's recent road relocation caused by a tanker truck fire. I thought I'd add a comment from the front, both geographically (since I'm in the Bay Area) as well as from the perspective of a company that supports a lot of location platforms that do routing.
One issue has been how to re-route motorists. A routing engine uses an algorithm to minimize road segment cost elements to calculate routes. However, in a case like this, the correct re-route isn't calculated by an algorithm; it's done by an official at the local road authority. That route is chosen to minimize impact on the surrounding community, is optimized to handle the traffic (within the limits of practicality...I hear it ain't pretty) and supported by local signage, traffic cops, etc. With something like 5,000 cars an hour dumping onto surface streets at rush hour, what they really don't want is for everyone (drivers or portals) to roll their own re-route. So routing engines need to be tuned to deliver the route approved by CalTrans, not just what seems best. And then you have to be sure you don't break anything else.
The second question raised is why all this attention paid to this closure versus all the others that happen across the country. Hint: It has something to do with the fact that it's local news for a lot of the big portals. I am not sure what response you would have gotten to a similar disaster on the busiest overpass in Dubuque, Iowa (presuming Dubuque has an overpass). But it does show the growing expectation for up-to-the-minute map data and the challenge for us in the industry to provide that.