We had about 2.8 million leave in about 1.5million cars.  

I know you guys like to blame the people themselves but the facts are only about 3-400 cars had gas mechanical problems out of 1.5million which caused a little more delay.  Most were pushed off of the road pretty quickly since traffic was so slow.

Is there anything that can be done?  Or do we just have to accept that more than half of the people will simply be affected by whatever people are bugging out from.  

IF we have to accept that,  do we need to take steps to ensure the threat cannot be spread? (assuming biological weapons, or radiation)

If it were nuclear or biological, the "authorities" would block the roads and bottle up the people to "contain the problem".