فراس حسن علوان أسد

Urban streets are essential parts in cities and their development can enhance various aspects of economic life and social activities. Al-Najaf city is one of the Iraqi developing cities that has been suffering from traffic congestion at various sections of its street network. The reasons, locations and intensities of these congestions are important to be regularly diagnosed for two key reasons: first, in order to choose the right traffic engineering solutions and second to adequately prioritize the funding required for planning and implementing the traffic management programs for these congested sections. This paper attempts to evaluate the performance of the main urban streets located within the southern part of Al-Najaf city street network during evening peak hours. The methodology includes collecting field data and conducting traffic surveys such as traffic volume, travel time and free flow speed surveys. The evaluating approaches illustrated in the U.S Highway Capacity Manual are adopted as a tool for assessing the operational performance for the selected urban streets. The results reveal that there are several segments that operate at their capacity (LOS E) or even under congested flow condition (LOS F). The analysis also shows that whereas some segments are with good LOS using volume-capacity ratio (v/c) criterion, they are actually with low LOS based on field observations or when using travel time as a performance measure. This indicates the inadequacy of using v/c ratio alone in evaluating urban streets because part of the congestion at such streets is due to side friction operational delays rather than over traffic demand.

The contribution of traffic signs in minimizing road collisions and maximizing traffic flow smoothness has been long recognized and agreed. The effectiveness of this contribution however largely depends on the driver’s cognition for these signs. This study aims to investigate the relative influence of driver’s socio-demographic factors on road sign cognition. Adopting non-experimental correlational research design, a cross-sectional travel survey with decent sample size (410 respondent) has been carried out in Al-Najaf Governorate (Iraq) in early 2017. A paper-based questionnaire has been designed and randomly selected drivers were asked about the correct meaning of 20 local road signs. The analysis shows that the overall comprehension level is just over 70%. Whereas driver’s profession, education and residence location are found influential, driver’s age, gender and marital status have no significant influence on sign understanding. In addition, several signs have been found with low understanding levels. As a result, official highway and traffic decision makers should take prompt actions. Initiating extensive and effective awareness campaigns and traffic education programs are of great importance. Priority should be given to drivers who are low educated, self-employed and live out of cities. The signs that have low understanding levels should be given top priority. The relatively large sample survey, the statistical-based evidence, and the lack of similar studies in Iraq make the findings of this study important and informative.

The overall aim of this paper is to enrich the global highway safety knowledge by shedding light on the current status of road safety in Iraq. Iraq is one of the major medium-income Arabic countries in which vehicular road transport is the essential means of mobility. Recently, there has been a noticeable increase in traffic accidents and injuries; this increase is expected to be as an intuitive result of the soaring motorization which in turned is expected to be a result of the boom in economy and population after 2003. Available evidence-based literature concerning status of traffic accidents in Iraq over the past decade (2005-2015) has been analytically reviewed. Such literature includes official statistics, traffic accident studies, and current highway safety policies and traffic laws. The discussion of the synthesis of evidence-based findings revealed several important points regarding aspects such as crash characteristics, occurrence, severity, and measures. The findings can be informative for researchers interested in studying highway safety in developing countries. Also findings can guide the government to achieve its national goal in minimizing accidents and injuries. The paper attains its significance from being the first paper among those available online with timescale, spatial coverage and analytical scope sufficient to consider the preset aim.

In the UK, TRICS is a national trip generation databases and system. It is recommended to be used in quantifying traffic impacts of new residential developments. Thus, any enhancement in its methodology will positively influence the transport assessment process. This paper has three objectives; first, to examine the possibility of proposing new statistically-proven grouping for the TRICS residential land use subcategories. The second objective is to use the proposed grouping to construct parsimonious models for home-based trip production that can aid in quantifying traffic impact assessment. The third objective is to examine the validity of the developed models against two of the most internationally recognised trip information systems; the UK TRICS and the US ITE Trip Generation Manual. The statistical analysis ended up with new more accurate grouping where based on it eight trip production model were built. The developed models were found to be practical and rigorous.

In this paper, route location selection is treated as a two end point boundary-value problem. The primary aim is to derive a computerized analytical solution, and then to design a computer program to determine the most cost effective route for a pipeline between two known terminal points. The terrain between the terminal points is heterogeneous in respect to cost, and hence, it is subdivided into multiple cost sub-regions with constant unit transportation costs. The cost sub-regions are separated by cost boundary contours. In order to simplify the solution derivation process only two cost sub-regions are considered separated by a single straight line to represent the cost boundary contour. The direct determination of the point of intersection of the route with the cost boundary line (corner point) is conducted analytically and exactly (without an iteration process). Various combinations of unit transportation costs have been studied to demonstrate the effect of cost ratio on the optimum route location. In order to achieve maximum cost savings, the study indicated that the pipeline route must be as short as possible in the region with relatively high transportation cost. It is demonstrated that the developed computerized solution is direct, valid and economical in terms of computation time.

The study aims to understand the city centre living characteristics from a sustainable travel behaviour perspective. Three datasets have been utilised; the UK Trip Rate and Information Computer System (TRICS), the Scottish Household Survey and an original household travel survey which has been conducted in Manchester city centre. An array of univariate and multivariate statistical techniques have been utilised to conduct the required travel analysis and modelling. Using Trics 2012a, exploratory analysis has shown a significant variation in the urban form characteristics between residential neighbourhoods located in central locations and those located in other areas. Households in the central locations generally travel less than others; in particular, town centre households walk more and drive less than others in out-of centre areas. In contrast, the inferential analysis showed evidence of a mediation effect whereby neighbourhood features such as the ratio of flats, parking density and transit provisions explain some of the differences in trip frequency. The mediation analysis also revealed that built environment features only partially account for these differences. The Scottish Household Survey and the Manchester city centre survey datasets have been utilised in order to investigate the potential impacts of several socio-spatial and attitudinal attributes on the city centre residents’ personal mobility. Whereas the review process disclosed the notable increase in the residents of the UK city centre and a revival of its housing sector over the past decade, the descriptive analysis revealed some distinct characteristics of those residents such as they are typically young adults, modern and well-qualified and living in single person households or as couples. Walking is their common mode for commuting, shopping and leisure. In Manchester city centre, 42% of the residents’ journeys were found to be within the city centre catchment area. In contrast, the travel behaviour models indicated the potential impacts of socio-spatial attributes such as car ownership, income and parking on mobility measures such as car ownership, mode choice and vehicular mileage. Finally, some attitudinal factors were found to be influential even after controlling for the socio-spatial effects.