Because you don't have any real evidence so you have to make up this "consciousness of guilt" garbage. It's desperate.
The point was that Whaley didn't always take the most direct route to get where he was going. Why would you assume that he would? Why would Oswald (if Oswald was even his passenger)?
Unscrupulous cabbies have been known to give a sucker a tour.... If the passenger isn't familiar with the area a cabbie will sometimes take the long way to the destination.....Particularly if the passenger is in a hurry to keep an appointment or is running late to catch a plane.....
Some unscrupulous drivers will promise to get the sucker to his destination if the passenger will pay an added charge. The driver will then take the long way and drive fast to earn the added bonus.