Sandworld — Richard A. Lupoff

Stranded on a strange planet with a race of alien vampires!

Red O'Reilly, the hero, is among three prisoners being transported by car with a guard and a social worker on a rainy night in contemporary California. Suddenly, in a flash, the car is off the road and into the middle of a jungle - which disappears as the rain ceases, leaving them stranded in a trackless desert!

After a trek across the desert, evidently on an alien planet far from earth, they discover a strange, ruined city inhabited by a race of vampire aliens - whom they must battle for survival.