Originally Posted by
westhawk
The point being, I'm not convinced there's any standard or rule applied consistently for US airports.
Annex 14 (which of course contains SARPs, not binding rules) simply says that one pair should be designated with the nearest 10° heading and the other pair with the next nearest. But then it also says that runway designator markings should always be 2 digits.
Horonjeff et al note that "this type of designation is increasingly being applied to three parallel runway configurations as well".