What is the theme of "The Hitchhiker" written by Lucille Fletcher and also redone by Rod Serling, but different?

The theme is Death coming to claim what is rightfully his.
The Hitch-Hiker is a ghost story. An ordinary motorist is on a cross-country trip (Brooklyn to California) and encounters a hitch-hiker who is constantly appearing. It then centres on the motorist’s attempts to shake the hitchhiker off.

http://www.playdatabase.com/play.asp?play=F297E60B-2D9C-441A-A08F-74F50F0B83EB

What the motorist doesn’t realise is that he is dead. He was involved (and killed) in a car accident on the first day of the journey and the hitch-hiker is Death.

http://www.allmovie.com/cg/avg.dll?p=avg&sql=2:183399