These NFHS/NCAA Football Rules Differences are presented in summary form and should only to be used as a guide; not all nuances are described. This information is in no way meant to replace the NFHS Football Rules Book. 2018 changes are shaded. These differences have been generously compiled and provided by George Demetriou, Football Rules Interpreter for Colorado. The NFHS is not responsible for content, accuracy or the maintenance of this information.