It seems like Dog the Bounty Hunter usually is the passenger, but he actually does drive sometimes on the show.
If you watched a lot of his show, you will noticed that he often has to jump out of the vehicle quickly to apprehend a criminal or suspected criminal, this is why he has someone else drive, so that he can get out rapidly to chase fleeing criminals.
The reality series followed Duane "Dog" Chapman, a Hawaii and Colorado-based bail bondsman, and his family and friends, as they tracked down folks on the run from the law and dealt with their own legal and personal issues.
The series debuted in 2004 and took a hiatus in 2007 after audio of Dog using a racial slur surfaced and caused a massive public controversy. Production resumed in 2008. In 2011, Dog's sons Duane Lee and Leland left the series. Season 8 last few episodes of "Dog the Bounty Hunter" have shown the Chapman family attempting to reconcile.
It was reported in May 2012 that A&E cancelled the TV series 'Dog the Bounty Hunter'. While no particular reason for the cancellation was reported, anecdotal reports suggest that frequent legal headaches stemming from the reality show may have played a part.