We introduce a simple yet efficient approach to optimize the modal fleet size of urban public transportation services, considering both user- and operator-oriented factors. This is envisaged to enhance the potential for achieving sustainable urban transportation systems and, eventually, opportunities to create sustainable cities. The presented constraint optimization approach can be described as follows. First, the expected passenger demand and the cycle time for the public transportation service are estimated. Next, the desired constraints and parameters, such as those related to the headway and seat supply, are determined. Finally, the optimal combination of different vehicle classes and the number of trips satisfying all the defined constraints are determined. The case of an urban area in a developing country is considered. The resulting solution determines the optimal numbers of public transportation trips and vehicles, by mode, required to meet the expected passenger demand, provide a high-quality service with acceptable headways for passengers, and, at the same time, reduce the service providers’ costs as well as the environmental impacts. It is also concluded that a fleet composed of different modes can better facilitate the achievement of the optimal solution for passengers and service providers compared with the one-mode fleet.

One of the major problems facing the newly established Palestinian National Authority (PNA) is traffic accidents. Several thousands of casualties are injured or killed in road accidents each year. In addition, the accidents form a considerable burden on the developing Palestinian economy. Since the establishment of the PNA in 1994 on parts of the Palestinian territories after years of Israeli occupation, changes in the political, demographic, and economic conditions are observed. Such changes resulted in increased motorization levels, and higher travel activities and traffic accidents. This paper addresses the developments in road safety in the Palestinian territories during the period 1970–1998. During this period, the number of reported accidents increased from 908 to 5945. The fatality rate per 10,000 vehicles reached to 14.2 in 1998. Such rate in the Palestinian territories in 1996 is about 4 times that of Israel, but forms about 75% of the respective rate of Jordan. The paper analyzes the development of road safety indicators before and after the establishment of the PNA. It investigates differences in road safety between the two physically-separated parts of the Palestinian territories, the West Bank and Gaza Strip, which exhibit different socio-economic characteristics as well. The paper also presents the major causes of accidents. Finally, a number of strategies, policies and actions are suggested to improve road safety in the Palestinian territories.

Several Traffic Systems Management (TSM) studies for Palestinian cities were conducted since 1995. Their objectives were better traffic circulation, less traffic congestion, management of the CBD parking, management of public transportation, traffic engineering improvement, and enhancement of administration and training capabilities. Each study identified an action plan for the respective city. The Municipality was identified as the primary agency that should carry on the TSM plans with local and international assistance. Several years after the completion of the TSM studies, the interaction of municipalities with the recommended action plans varied among these cities. The impact of the TSM studies in each city after several years have passed was evaluated. Interviews with city officials were conducted to assess the status of following through study recommendations. Some action plan items were conducted because of their high priority, availability of funds, and public demand. Other improvements were not implemented because of their low priority, lack of funds, high cost, public objection, and political conditions.

Fuel consumption and exhaust emissions are directly related to traffic movement and vehicle speed and acceleration/deceleration. Vehicular traffic in the Palestinian areas consumes approximately 60 percent of the total fuel consumption. Therefore, the continuous growth in the number of vehicles in general and passenger cars in particular will increase fuel consumption and emissions in the area. The objectives of this study are to evaluate the impact of traffic signals and their improvements on traffic movement and delay and to link traffic measures of effectiveness (MOE) with fuel consumption and air pollution in Nablus City downtown area. CORSIM simulation model was used as a tool to estimate traffic and environmental MOE. Studies showed that traffic signal improvements in urban areas could lead to a reduction in fuel consumption and exhaust emissions in percentages ranging from 25 to 65 percent. In this study, traffic signals were improved at study intersections and corridors in downtown Nablus City using optimum cycle length, signal timing, and progression. These improvements resulted in reducing average delays by 3 to 57 percent, fuel consumption by 2 to 25 percent, and carbon oxides air pollution by 2 to 10 percent. The study recommends improving traffic circulation and reducing fuel consumption and emissions using traffic signal improvement plans at the network level in downtown Nablus City. The implementation of traffic systems management, which includes low cost and quick to implement plans, is also recommended to improve traffic and environmental conditions in Palestinian cities.

The Israeli occupation authorities started in April 2002 the construction of the segregation wall on confiscated Palestinian land for claimed security reasons, ignoring the international law which does not allow the occupier to do that. The Wall, when completed, will isolate parts located between the wall and the 1949 Armenistic Line, forming 46% of the total area of the West Bank. The results of the field study indicate that there will be severe impacts of the wall in the field of transportation. The wall will lead to severe deterioration in the Palestinians quality of life, as it will restrict the movement and free transportation for 647 thousand Palestinians forming one third the Palestinians living in the West Bank, including restricting their ability to reach their agricultural land. The wall cuts off public transportation lines for a number of communities which the wall isolates. The number of links connecting a community with others is reduced for many of the impacted communities, while about half the total length of the roadway network in the West Bank will lie behind the wall. The Israeli measures cause the length of, and travel time on, the roads connecting these impacted communities to at least double on the average, and therefore, result in a similar increase in travel cost. Therefore, the wall will affect the sustainability of the transportation systems and will prevent such systems from playing the role they should provide towards sustainable development in the Palestinian territories. The paper presents a number of recommendations to pressure the Israeli authorities to stop building the wall, and to assist the Palestinians living in the impacted areas in their struggle against the challenges they are facing, through means that lessen the negative impacts of the wall, especially those which affect the sustainability of the transportation systems. لقد باشرت سلطات الاحتلال الإسرائيلي في نيسان 2002 إنشاء جدار الفصل العنصري على أراضٍ قامت بمصادرتها من أصحابها الفلسطينيين، حيث قررت إنشاء الجدار عليها لأسباب أمنية مدعاة، ضاربة بعرض الحائط القوانين الدولية التي لا تجيز ذلك للمحتل. وسيعزل الجدار، عند اكتمال بنائه، أجزاء تقع بين الجدار وخط الهدنة لعام 1949، تُشكل حوالي 46% من مجمل مساحة الضفة الغربية. وتبين نتائج الدراسة الميدانية حول تأثير الجدار السلبي في مجال النقل والمواصلات أن الجدار سيؤدي إلى تدهور خطير في نوعية الحياة للمجتمعات الفلسطينية، حيث يقيد أو يمنع الحركة وحرية الانتقال لحوالي 647 ألف فلسطيني، أي ثلث الفلسطينيين المُقيمين في الضفة الغربية، بما في ذلك إمكانية وصولهم الى أراضيهم الزراعية. وفضلاً عن هذا، فإن هناك تأثيرا غير...