ANALYSIS OF THE EFFECTS OF THREE WHEELERS ON PERFORMANCE MEASUREMENT PARAMETERS OF INTERSECTIONS: A CASE STUDY: ROUNDABOUTS AND SIGNALIZED INTERSECTIONS IN HOSSANA CITY

Abstract

Traffic intersections are complex locations on highways. This is because vehicles moving in different direction want to occupy same space at the same time. Traffic volume is one of the variables that have the biggest effect on intersection performances. The traffic volume of Menharya and Maryam signalized intersections, Bezabh Petros and Eyerusalem roundabouts at Hosanna city is highly occupied by three wheelers. So it is vital to study the effects of three wheelers on performance measurement parameters of intersections. The other purposes of the study were, analysis of existing intersection performances, evaluation of the consequences of three wheelers with performance parameters and comparing the performance change of intersections by replacing three wheelers with a minibus. All data were collected by using video camera for traffic data and measuring tape for geometric data. By taking peak hour volume, the performance measurement parameters of intersections were done using HCM 2010 methodologies incorporated in SIDRA Intersection Software 5.1. The effects of three wheelers on intersection performances were evaluated by excluding three wheelers from analysis and by comparing each performance parameter changes with and without three wheelers. By replacing three wheelers with minibus of 12 seats, the performance changes of intersections were evaluated and compared well. From the result of the study, Menharya signalized intersection is operating above its capacity because, the degree of saturation of this intersection is 1.374 which is greater than one and Maryam signalized intersection also shows congested condition with degree of saturation 0.852. 70.5% cause for delay, 85.5% cause for a degree of saturation, and 93.8% cause for the queue distance of Menharya signalized intersection is the presence of three wheelers. In the same manner for Maryam signalized intersection, 17.1% cause of delay. 82.2% cause of degree of saturation, and 90.7% cause of queue length is three wheeler's presence. The performances of both roundabouts are also affected highly due to presence of three wheelers. For Menharya signalized intersection, 54.1% Average delay, 31.7% degree of saturation and 59.5% queue distance, For Maryam signalized intersection, 19.3% Average delay, 32.4% degree of saturation and 45.6% queue distance is improved when Three wheelers replaced by minibus.