تصنيف وتقييم الطرق الحضرية في مدينة كربلاء

Classifying and Evaluating Urban Streets in Karbala City

Abstract

Karbala is distinguished by its religious and touristic charactertersitcs which attracts numerous tourists throughout a whole year, and are consistent with many of the establishments that have sprung up throughout the city including universities, hospitals, shopping centers, and others, which has increased traffic congestion,and traffic accidents. Setting the essential actions to enhance traffic performance and decrease delays requires understanding how well the road networks are working. This research intends to categorize and assess urban roadways in Karbala city. The study area consists of thirteen streets were divided into several segments. Field data collection on selected roadway segments is performed using the video-camera method. The specific camera is used (2 Megapixels of excellent performance, Analog HD output with a maximum resolution of 1080p, and Day/Night switch).This method help in extracted data such traffic volumes and the elements of Side Friction (SF) (street parking and pedestrian crossing). The travel time for all segments was calculated using a floating car, and free flow speed was determined by using a radar speed gun device. In first stage, urban roads were classified based on free flow speed . Results showed that most segments work within Class Ⅱ and the rest are divided between Classes Ⅰ, Ⅲ, and Ⅳ.
In the second stage, urban roads were evaluated by determining the Level Of Service (LOS) based on the Highway Capacity Manual (HCM 2000, HCM2010), and by performance measures including travel time, corresponding travel speed, and free-flowing velocity to assess each part of the network. Required field traffic data were measured during the morning (7:30 AM-9:30 AM) and evening hours (12:00 PM – 2:00 PM)and(4:00PM-6:00PM) during peak hours.
The third stage evaluates the road network by using several indices for the city of Karbala: Alpha, Beta, Gamma, and Grid Tree Pattern using GIS software. Study results show that the network is weakly interconnected (α= 0.4885, β = 1.75, γ = 0.6, GTP= 1.21).
Then, the results of LOS for that most urban roads have a value of (v/c) higher than one indicating the presence of crowded streets. While some sections of urban roads were found with good service levels when using (v/c) according to HCM2010. They were found to have low service levels when using average travel speed. This indicates that some of the congestion may be brought on by the existence of side friction. The effect of SF on all selected streets( Al-Iskan Street, Fatima Al-Zahraa Street, Al-Abbas Street, and Al-Tarbia street) during the morning and evening periods was very high according to the Indonesian Highway Capacity Manual 1993 (IHCM) where he reached the first segment in the evening of Al-Iskan Street (3890 Event/hr), Fatima Al-Zahraa Street( 4671 Event/hr), Al-Abbas Street(3312 Event/hr) and Al-Tarbia street (5392Event/hr), which affected the capacity of the street and reduced the speed by about 51%.