1. A factor, also known as the design hour factor, which represents the proportion of Average Annual Daily Traffic (AADT) expected to occur in the design hour.
2. K-Factors or Bias Factors are zone to zone bias factors other than travel time that are specific to an that affect travel patterns. Also referred to as friction factors, K-factors are estimated based on a comparison of origin destination surveyed zone to zone movements to the same zone to zone movements estimated using a gravity model.