Transformers are the laziest robots we've ever seen. After all, Optimus Prime is a lorry - so can't he drive himself to work? Does he really need a backie from one of his mates? And Barricade's just as bad.
We don't know, these Hollywood types and their egos. Hit the link to go to Superhero Hype for a better look at Prime's drive to work.
Sources: (Superhero Hype)