Traffic is a valid concern when picking and taking escape routes, especially local traffic, which I'd say is potentially more hazardous than yahoos or armored vehicles. You can minimize its impacts by avoiding traffic in general, taking your escape route as soon you recognize you might encounter traffic, and having multiple options for escape routes. I'm not saying you can't absolutely prevent that worst case scenario where you suddenly have to execute an escape, have only one option, and then encounter traffic. However, if you're diligent, I think you could certainly minimize the chances that this could occur such that it would be quite rare. Brindley and I are always on the move whenever we see a clump of cars coming down our route, and actively work to avoid knots of stopped chasers, just to maintain our spacing from them.
To be honest, if a few cars mean the difference between a clean escape and an impact, then you probably need to reassess your chase strategies and level of risk. It's more of, "What am I doing here?" rather than, "What are they doing here?" Take responsibility for being caught in traffic when you need to escape, rather than blaming the traffic, downed tree, flooded road, or whatever else is blocking your escape.
