The largest metro area in my region is (thankfully) about 70 miles away. It contains more than 4.8 million registered vehicles. A forced mass evacuation would put nearly 28,000 miles of vehicles on six evacuation routes (4,600 miles per route if distributed evenly). Unless you are in the front of that herd it could take several days to reach your intended destination. And, of course, all fuel or food sources will have been depleted before you reached them. Resupply would be impossible. If you are fortunate enough to escape your city, every town that you pass through, including my own, will have already been overwhelmed by the evacuation. We have just two grocery stores and six small gas stations. You will not be welcomed. In all probability, roads leading into our town will already be barricaded. Good luck.