Investigation of vehicle bunching at signalized arterials in Turkey

The objective of this study is to investigate the proportion of free vehicles on signalized arterial roads near the signalization points (up to 400 m) in Turkey. Vehicle-lime headway data are obtained from two different cities: four signalized intersections and five mid-block traffic signals in Izmir and four signalized intersections in Denizli. The current methods for describing the proportion of free vehicles on a road link are investigated and an exponential relationship is suggested for modeling the proportion of free vehicles. The results are considered with respect to both the lane type and the traffic volume. The characteristics of the traffic flow and proportion of free vehicles were found to be dependent on the lane type. Key words: signalized intersections, proportion of free vehicles, Cowan M3 distribution. La presente etude a pour objectif d'examiner la proportion de vehicules libres pres de carrefours a feux (jusqu'a 400 metres) sur des arteres avec feux de circulation en Turquie. L'espaeement temporel entre les vehicules est obtenu pour deux vines, quatre carrefours a feux et cinq feux de circulation a mi-chemin d'un pate de maisons a Izmir et quatre carrefours a feux a Denizli. Les methodes actuelles de description la proportion de vehicules libres sur une route sont examinees; une relation exponentielle est suggeree pour modeliser la proportion de vehicules libres. Les resultats sont etudies en tenant compte du type de voie de circulation el du debit de circulation: ils montrent que les caracterisiiques du debit de circulation et la proportion de vehicules libres sont fonction du type de voie de circulation. Mots-cles : carrefours a feux, proportion de vehicules libres, distribution Cowan M3. [Traduit par la Redaction]
Introduction Statistical modeling of traffic flow headways has a wide range of applications in traffic engineering, such as gap-acceptance process for estimating capacities of sign-controlled intersections or roundabouts; queuing at [...]