The rider of the Yamaha dirt bike, Frisco Davidson-Spurs Yankolovich, was transported to a local hospital where he died of his injuries. Police said the 20-year-old was wearing a helmet at the time of the collision.
The rider of the quad stopped and looked at the victim then left the scene, according to Phoenix police Sgt. Tommy Thompson.
Police say that man, 48-year-old Gregg Creevy, is facing charges of leaving the scene of a fatal collision and tampering with evidence.
Witnesses said they frequently see the man riding in the desert and he has helped construct a number of the off-road jumps in that area.