Standard procedure nowadays - at least in some areas. The officer is in less danger from passing traffic if they are on the passenger side of the car. There are also advantages of getting a different view into the car and throwing the driver off guard by doing something other than what they expected.
http://ipmba.org/blog/comments/passenger-side-vehicle-approaches
http://www.lawofficer.com/article/patrol/passenger-side-approach
Ok thanks. But I haven’t seen that here I can recall on most stops. The officer angles out the front of his car to cover him from a sideswipe.