The purpose of this subpart is to implement the requirements of 23 U.S.C. 150(c)(4), which requires the Secretary of Transportation to establish performance measures for the purpose of carrying out the Highway Safety Improvement Program (HSIP) and for State departments of transportation (State DOTs) to use in assessing:

(a) Serious injuries and fatalities per vehicle miles traveled (VMT); and

(b) Number of serious injuries and fatalities.