Several years ago, my area went to concrete-encased electrodes on all new construction. I don't know how it is usually done, since I have rarely been involved in that phase of the job and now I generally don't do new construction at all.
For the past year, I have been using a type of concrete-encased electrode that has been recommended to me by several local AHJs, and that is due to be adopted as the standard for existing construction.
I dig a hole 30" deep and 24" diameter, and place 25' of coiled bare #2 Cu at the bottom. Add a bag of Quikrete, mix in water, then backfill. One AHJ advised me to leave the bag on the ground nearby, with a hose available, so he could pour it in himself after inspection.
I started using this method on the west side of town, where driving ground rods is frequently close to impossible. Word is ground rods will soon be eliminated altogether.
