People killed or seriously injured (KSI) is used as the metric for roadway safety rather than simply fatalities because fatalities alone tend to be random in nature and can obscure long-term trends. Including serious injuries makes the data more robust and better highlights how the region is doing at preventing serious vehicle crashes. This approach has been promoted by the FHWA and embraced by both NJDOT and PennDOT. Because KSI can fluctuate from year to year, five-year rolling averages are used to identify trends, as seen in the first chart. The data separates pedestrians and bicyclists from motor vehicle occupants because these users are more vulnerable to death or serious injury when involved in a crash. Data for motor vehicle and combined bicyclist and pedestrian KSI u KSI can be looked at as a raw total, normalized based on population (per capita), or based on vehicle miles driven (per VMT).