Helmet Positioning Index Law and Legal Definition
According to 16 CFR 1203.4 [Title 16 -- Commercial Practices; Chapter II -- Consumer Product Safety Commission; Subchapter B -- Consumer Product Safety Act Regulations; Part 1203 -- Safety Standard for Bicycle Helmets; Subpart A -- The Standard], helmet positioning index ("HPI") is “the vertical distance from the brow of the helmet to the reference plane, when placed on a reference headform. This vertical distance shall be specified by the manufacturer for each size of each model of the manufacturer's helmets, for the appropriate size of headform for each helmet”
