If people in the US don't move over when an ambulance is on their bumper with lights and sirens blaring ... there's no chance they would think ahead and clear a path just in case.
I was in stopped traffic last week. 3-lanes, dead stop. Here comes an ambulance about a half-mile back. His only option is the shoulder. But there're cars on the shoulder too trying to either get a look at what stopped the traffic or gain some sort of advantage in traffic. So the ambulance is running through the grass drainage swale