Jet Blast is dangerous. You shouldn’t walk or drive a car behind a powered up jet.
Jet engines are really powerful. Hurricane force winds can extend up to 600 feet behind the jet. The blast behind the engines can be so powerful that it can lift cars, buses, and definitely people. NASA put together a great safety guide on how to operate in congested ground areas with jet aircraft. If you are too lazy to read it, here’s the short version: stay away from the ass end of a jet engine.
A couple of years ago, the boys at Top Gear decided to see just how dangerous jet blast actually is. They proved that driving behind a jet engine might kill you. It’s not a smart idea.