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 urban area 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.