A new quality measure for assessing trip tables estimated from traffic counts

The uncertainty of an origin-destination (O-D) trip table estimate is affected by two factors: (i) the multiplicity of solutions due to the underspecified nature of the problem, and (ii) the errors of traffic counts. In this paper, a new quality measure for assessing the O-D trip tables estimated from traffic counts is proposed. This new quality measure consists of two parts: (i) a generalized demand scale (GDS) measure for quantifying the intrinsic underspecified nature of the O-D estimation problem at various spatial levels, and (ii) confidence intervals to quantify the contribution of input errors (traffic counts) to the estimation results. Initial results using PFE (path flow estimator) as the O-D estimator show that the new quality measure is able to separate the two sources of uncertainty in constructing the confidence intervals at various spatial levels. Simulation results also confirm that the proposed quality measure indeed contain the true estimates within the defined confidence intervals.