A multivariate analysis study was conducted of vehicular speeds on 2-lane rural highways to gain a better understanding of traffic stream characteristics through the formulation and evaluation of mathematical models describing the time-rate of traffic flow. The concept of traffic flow was founded on the assumption that vehicular speeds are a function of various travel conditions present in and adjacent to the traffic stream. Thus, various types and levels of travel features produce different average spot speeds. The total effect of these resistance variables determines the speed characteristics of a particular highway location. The description of this traffic-flow concept was accomplished through the development of multiple linear regression equations. Two mathematical models were devised to relate mean spot speed as a function of generated factors in one equation and of travel- restriction variables in the other expression. These regression models were restricted by the assumption of linearity in both the variables and the parameters.
Abstract