Doesn't sound like a very good plan, with either one incident locking up all the radio traffic, or just one radio with a stuck key intentionally or not could bring the whole system down. They need to do a little more work with Incident Command planning. Personally I think this is their way of getting lots of free equipment at taxpayer expense.
As far as closing down an interstate highway, (sigh) beginning to look more like the old USSR here. The more extreme measures taken, result in even more extreme measures taken by the opposition.