Investigation of breakdown event at merging section of Federal Highway

Congestion is an issue that continuously occurs on urban roads which is part of a so-called breakdown phenomenon. Breakdown can be defined as the transition between proper operation and non-acceptable flow conditions. This study was carried out to determine the speed-flow relationship with respect to breakdown event at the Federal Highway as well as to analyse time series for flow rate and speed in order to justify the breakdown occurence. Data consist of speed, traffic flow, density, and several others were collected by the Automatic Incident Detection device. The speed-flow curve was reconstructed using the Greenshields Model. Based on the model obtained, value of maximum flow rate is 1634 veh/hr/ln and the critical speed is 65 km/h. Understanding the breakdown phenomenon at merging sections is a key parameter for more effective geometric design and control strategies.