If anyone knows how to get the design report for this project, it would be interesting to see what alternatives they had to closing the NB101 for up to 21 days. The commute for North County residents just got worse, and the tourist traffic isn't going to be pleased, either.
In my experience a common alternative is to use subsurface techniques (called jacking) to install or replace a culvert without causing the road to be shut down. There must be a good reason why this technique can't be used in this project as Caltrans know better than to shut down a road like this without a good reason. Don't they?