This is truly an interesting subject - I suppose it would be like the wildfires - ask people to evacuate and you know not all will.. I probably wouldn't.. I'd probably set up a tent in the back yard and wait it out.. As they say, it's not the earthquake that kills you.. it's the buildings.

Rather than grid-lock, maybe evacuation centers in large parks or open spaces could be designated - heck, they could even bring in port-a-potties and keep them 'closed' until after the shaking..

It would save lives.. you are going to have the infrastructure damage whether it's predicted or not. You could take the time to shut down hot nuclear reactors.. and any other dangerous manufacturing processes.. get the fire trucks out of the garages, etc..

I truly think there is a lot that could be done.. without creating gridlock.. and panic..

Canie