Evaluating the operational performance of urban streets within Al-Najaf city.

Cities' streets are vital components and their performance can improve a variety of social and economic aspects. Al-Najaf is one of the growing cities in Iraq that has been experiencing congested flows on several portions of its street network during morning peak hours. The causes, locations, and severities of these traffic jams must be detected on a regular basis for three reasons: first, to elect the best traffic solutions; second, to properly prioritize the resources needed to conduct traffic management schemes for these congested segments; and third, to aid in quantifying the raised traffic congestion costs. This article seeks to assess the traffic performance of selected streets located in the southern section of Al-Najaf city network during morning rush hours. The methodology involves conducting field inspections and performing traffic studies such as traffic volume, journey time, and free flow speed studies. The US Highway Capacity Manual's methods (ed. 2000 and ed. 2010) have been used to determine the service level of the chosen streets. The analysis results proved that about third of the segments are with Class II classification due to the relatively low free flow speed. According to HCM2000-and HCM2010-based analyses, eight of the 34 studied directed segments have been found with unstable or bad traffic operational performance (LOS D, LOS E or LOS F). Sixteen directed segments have the same LOS based on the both HCM editions, nevertheless, for the rest segments, HCM2010-based results are relatively more conservative than HCM2000 ones. Finally, the analysis also revealed that there is a potential impact of the street roadside's developments on the time of traffic peak hour (morning vs. evening). The drawn findings could be informative for highway and traffic firms and researchers alike. [ABSTRACT FROM AUTHOR]