Calibration courses on concrete roads are best made irregular lengths, so that they can lie between two permanent fixtures (drain edges, pavement cracks etc).
I've heard of people using a concrete drill to make holes in which to put PK nails. I won't do this, as I rarely put in PK nails at all, except perhaps on bike paths in the middle of unfeatured woods, or on calibration courses on asphalt roads. Too many of the courses I measure change from time to time, and if I had been nailing I'd have them all over the place.
Lately I have taken to photographing the splits and giving a photo CD to the race director. I have found that this serves to refresh my memory too.