This really doesn't work. You can sense they wanted a US post apocalyptic wasteland, and a guy needing to traverse it (so pregnant lady on the other side obviously) but they never seem to have thought about how to land in that situation. So a vague thing happens on the West Coast and America turns into a failed state instantly, people turning outlaw basically by breakfast. The rest is as hastily thrown together as the plot. Maybe they were counting on the sequel to give a bit of context? Either way, we are not going to get it.