In the day following the Rider's first ride, Cage shows up at the street that has been burned down the center. A person very close to the beginning of that scene walks on the broken up rocks and it moves as if it were a pad or a sponge. It wasn't a rock moving because the street moves with the rock. It happens a couple of times during that scene.
The bike Johnny rides is a modern version of the one Peter Fonda (the devil in this movie) rides in Easy Rider, ironically named the "Captain America." He even says to Johnny "nice bike."