THE ESTIMATION OF JUNCTION TURNING VOLUMES FROM TRAFFIC COUNTS: THE ROLE OF PRIOR INFORMATION

Many authors have pointed to the importance of prior information when estimating an origin-destination matrix for an intersection from measurements of certain (usually the inflow and outflow) traffic streams. This paper reviews ways of obtaining prior information, giving particular attention to a sampling technique. There is usually an element of uncertainty associated with the values chosen for the parameters representing the prior information. An expression is derived which gives the variances and covariances for the logarithms of the fitted turning volumes implied by variances and covariances for the logarithms of the prior information parameters. The procedure is applied to the Hansemannplatz intersection in Aachen, West Germany. (Author/TRRL)