Modeling of Daily Speed-Flow Relationships Considering Road Condition and Traffic Flow Variations

Abstract

In the road project evaluation, cost-benefit analysis is conducted using the daily speed-flow relationship (Q-V), which is uniformly determined according to the road types and number of lanes. However, the existing Q-Vs cannot accurately reflect actual road traffic conditions, and they did not sufficiently take into account regional traffic conditions. In order to fill these research gaps, in this study, Q-V using traffic flow variations and the hourly speedflow relationship (q-v) considering road structure and traffic operations is modeled. The time average travel speed for each time period is calculated by using the traffic flow variations of the actual observed data and q-v. Then, by taking the weighted harmonic mean of these values, the daily average travel speed of a certain daily traffic volume was calculated and Q-V was set. The shape of the Q-V curve can be explained by the traffic flow variations, and the estimated model made it possible to estimate the Q-V considering the actual road and traffic conditions.