Factors Affecting Road Capacity Under non-Ideal Conditions in Egypt

Ahmed Ebrahim Abu El-Maaty


The The road capacity reduction is the biggest problem that faces many developed countries specially Egypt. It has caused many problems in the highway traffic congestion and delays. The road capacity value drops due to various non-ideal conditions which includes changes in speed or travel time, traffic interruptions or restriction etc. In this study, the factors that cause road capacity reduction under the non-ideal conditions in Egypt such as lane width (FLW), heavy vehicle (FHV), driver population (FDP) and environmental factor (FE) are discussed and simulated through a case study using SYNCHRO software. The studied factors are divided into categories. The first group includes 8 factors that are part of the software and excluded from the capacity calculation equation and consequently, are substituted by the value of 1 in the capacity calculation. The second group includes 3 factors that are inserted in the capacity equation using various values. The third group includes 1 calibration factor (driver population) which needs to be adjusted to get the real field capacity. Different values of this factor are tried in the simulation until the traffic conditions are visually close to the reality. The optimum value of the calibration factor has been obtained as 0.817. Finally, incidents, which is a variable and unexpected factor, and occurs in non-conventional conditions has been studied. The capacity reduction caused by incidents was best modeled as a random variable, not a deterministic value, as is the current practice.

Key words: Road Capacity; Traffic Congestion; Non-Ideal Conditions; Incidents Factor; Driver Population Factor; Lane Width Factor.

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DOI Prefix: 10.20286