Determining Roadway Capacity Using Direct Empirical Methods

Estimation of a capacity of transportation systems and facilities is one of the major issues in traffic flow analysis. Capacity of a roadway can be estimated using direct or indirect empirical methods. The focus of this project is the estimation of a roadway operational capacity using four direct empirical methods (i.e. Generalized queuing model, Selected Maxima,Product Limit Selection and fundamental diagrams). The methods were used to estimate roadway capacity values using the traffic data obtained from Pontian Highway in Johor Malaysia. The results shows that the capacity values obtained with product-limit-selection method were closer to the observed maximum volumes for all the averaging time intervals(i.e. 5min,10min, 15min) considered. The next method that has capacity values closer to observed maximum volumes was fundamental diagram method. Headway method was found to have higher and exaggerated capacity values compared to the observed maximum volumes.fundamental diagram method was found to be the most suitable method because it takes in to account the finite nature of the road section by including density in the analysis.