I found a few videos that explain the 90 degree cart rule.  We appreciate your cooperation.  This will help us provide high quality playing conditions for all to enjoy.  Note that it is different than most Zoysia courses.  Zoysia is a warm season turf that withstands heat, drought, and traffic much better than cool season turf.  Our entire golf course is cool season turf that is more delicate.  This is the reason for the 90 degree rule.  We use the 90 degree rule all season.  If we are off the path the 90 degree rule is in place.