فهرست مطالب
مجله مهندسی عمران شریف
سال بیست و هفتم شماره 3 (پاییز 1390)
- ویژه ی حمل و نقل شهری
- 108 صفحه، بهای روی جلد: 70,000ريال
- تاریخ انتشار: 1390/12/15
- تعداد عناوین: 12
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صفحه 0
- مقالات پژوهشی
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صفحه 3در این نوشتار ابتدا با استفاده از دو مدل دادهستانده (I O) و ماتریس حسابداری اجتماعی (S A M)، تاثیرات افزایش قیمت حامل های انرژی بر هزینه ی انواع خدمات حمل ونقل آبی، هوایی، جاده یی و راه آهن، مورد سنجش قرار گرفته است. سپس تاثیر افزایش قیمت حامل های انرژی بر هزینه ی خدمات حمل ونقل درون شهری اندازه گیری، و اثرات رفاهی اجرای قانون هدف مندسازی یارانه ها بر دهک های هزینه یی خانوارهای شهری ارزیابی شده است. نتایج تحقیق گویای آن است که:1. میزان افزایش هزینه ی خدمات حمل ونقل بسیار درخور توجه است. هزینه ی استفاده از خودرو شخصی 195درصد و هزینه ی تولید خدمات حمل ونقل عمومی در شهرها 48٫6درصد افزایش خواهد یافت. از این رو خانوارها بیش از گذشته از وسایط نقلیه ی عمومی استفاده می کنند و در درازمدت خودروهای کم مصرف جایگزین خودروهای پرمصرف خواهد شد. 2. جز دو دهک اول، بقیه ی دهک ها از اجرای طرح متضرر می شوند. در این وضعیت لازم است دولت از پرداخت یارانه ی دهک با درآمد بالا اجتناب کند.
کلیدواژگان: قیمت حامل های انرژی، هزینه ی حمل و نقل، اثرات مستقیم بر هزینه ی تولید، اثرات غیر مستقیم بر هزینه ی تولید، اثرات رفاهی -
صفحه 17رقابت بین سرعت توسعه ی زیرساخت های حمل ونقل و رشد تقاضا، پدیده یی پیچیده و دنباله دار است که مشکلات ترافیکی و زیست محیطی و نیز اختلال در سلامت جسم و روان جامعه پیامدهای منفی آن است. رویکرد نوین مسئله، شامل تعریف متفاوت و جدید مسئله، مبتنی بر مدیریت کاراتر است. یکی از تعاریف درست و دقیق «تقاضای حمل ونقل» با توجه به مشتق بودن این تقاضا دست یابی به هدف سفر بدون نیاز به انجام سفر فیزیکی است. مدیریت تقاضای حمل ونقل، با رویکردی علمی به دنبال دست یابی به اهداف سفر با کم ترین تعداد سفرهای فیزیکی است. در این نوشتار اثرسنجی به کارگیری دورتحصیلی به عنوان یکی از راهکارهای مدیریت تقاضای سفرهای تحصیلی در شهر مشهد ارائه شده و تلاش می شود رابطه یی ریاضی بین مقدار صرفه جویی ریالی حاصل از اجرای سیاست های مدیریت تقاضای دورتحصیلی ارائه کند. نتایج این نوشتار می تواند مدیران شهری را در کاهش سفرهای تحصیلی در قالب راهکاری برای مدیریت تقاضای حمل ونقل با تعریفی درست از مسئله یاری کند.
کلیدواژگان: توسعه ی پایدار اقتصادی، دور تحصیلی، مدیریت تقاضای حمل و نقل، مشهد -
صفحه 23ه منظور بهبود شرایط ترافیکی شهرها، اخیرا رویکرد نوین چندسیاستی مدیریت تقاضای حمل ونقل به عنوان جایگزین رویکرد ک سیاستی مطرح شده است. در این مطالعه طراحی روش اجرا و شناسایی میزان اثرات چند سیاست مدیریتی هم زمان در مدیریت تقاضای حمل ونقل شهری بررسی شده است. در این راستا علاوه بر اثرات اصلی سیاست ها، آثار ترکیبی سیاست ها نیز در طرح آزمایشی مطالعه مورد توجه قرار گرفته و پنج سیاست مدیریتی حمل ونقل شامل: سیاست های کاهش زمان سفر سیستم های همگانی، بهبود دسترسی به سیستم های همگانی، قیمت گذاری سوخت، قیمت گذاری پارکینگ، و اخذ ورودیه به مرکز شهر در سفرهای کاری به مرکز شهر تهران بررسی شده است. با گردآوری رجحان های بیان شده 366 نفر استفاده کننده از سواری شخصی، مدل انتخاب وسیله ی مسافران در قالب یک مدل لوجیت چندگانه تهیه شد و نمودارهایی برای نشان دادن کاربرد مدل برای سیاست گذاری ارائه شده است.
کلیدواژگان: مدیریت تقاضای حمل و نقل، سیاست های هم زمان، اثرات حاشیه یی، سیاست گذاری، مدل لوجیت -
صفحه 33در سال های اخیر استفاده از سامانه ی اتوبوس های تندرو (B R T) در شهر تهران مورد توجه بوده است. گسترش چنین سامانه هایی نیازمند تعیین دقیق اثربخشی آن ها در کاهش اثرات ناشی از آلودگی هوا و بهبود ترافیک است. در نوشتار حاضر اثربخشی راه اندازی خط B R T در حد فاصل پارک وی تا میدان تجریش در رابطه با مسائل زیست محیطی، فرهنگی و اجتماعی مورد بررسی قرار گرفته است. این تحقیق مبتنی بر تهیه ی پرسش نامه و اندازه گیری های میدانی بوده و در دو مرحله)قبل و بعد از راه اندازی خط(صورت پذیرفته است تا نتایج قابل مقایسه باشند. تحقیق حاضر نشان داد که بارزترین اثر اجتماعی اجرای این طرح کاهش هزینه های اجتماعی ناشی از انتشار کم تر آلاینده ها و نیز کاهش میزان مصرف سوخت بوده است. منافع حاصل از کاهش هزینه ها می تواند در اقدامات اصلاحی، نظیر نصب دیوارهای کاهش آلودگی صدا، مورد استفاده قرار گیرد.
کلیدواژگان: حمل و نقل، آلودگی، اتوبوس، سوخت، هزینه های اجتماعی -
صفحه 41ز معضلات اساسی شهروندان، به ویژه در کلان شهرهای ایران، «ترافیک شهری» است. با توجه به رشد جمعیت و ناوگان، افزایش زیرساخت ها بیش از این پاسخ گوی جابه جایی نبوده و زمینه های رشد بیشتر آن نیز فراهم نیست. بنابراین، مدیریت تقاضای حمل ونقل در سال های اخیر اهمیت ویژه یی یافته است. هدف این نوشتار، مقایسه ی راهکارهای مدیریت مصرف سوخت حمل ونقل شهری در ایران با یافته های یک روش رده بندی کمی است. بدین منظور ابتدا راهبردهای این حوزه)13 مورد(و راهکارهای زیرمجموعه ی هر راهبرد)44 مورد(که در 14 کشور اجرا می شوند، گردآوری و در 3 گروه)ناوگان، حمل ونقل، سوخت(دسته بندی می شوند. سپس این راهکارها با استفاده از روش نقطه ی آرمانی اولویت بندی می شوند. براساس نتایج حاصله، سه راهبرد برتر عبارت اند از: گسترش حمل ونقل عمومی)به ویژه ریلی(، گسترش حمل ونقل هوشمند و گسترش منابع انرژی. چهار راهکار برتر نیز عبارت اند از: گسترش شبکه ی عمومی، گسترش و کاربرد I T S و ابزارهای کنترل ترافیک برای کاهش تراکم و مصرف سوخت، بهبود دسترسی به حمل ونقل عمومی، گسترش و سرمایه گذاری در انرژی های تجدیدپذیر. مقایسه ی یافته ها با آنچه در کلان شهرهای ایران اجرا می شود نشان می دهد که تنها وجه مشترک، راهبرد گسترش حمل ونقل عمومی و دو راهکار آن است و دیگر گزینه های پیشنهادی احتمالا به سبب تعریف نادرست یا ناکامل مسئله مورد کم توجهی قرار گرفته است.
کلیدواژگان: مدیریت مصرف سوخت، حمل و نقل شهری، راهبردهای صرفه جویی سوخت، اولویت بندی راهکارها، روش نقطه ی آرمانی -
صفحه 53ضای ورودی شهرها به عنوان یکی از فضاهای شهری و مفصل اتصال دهنده ی فضای طبیعی خارج و فضای مصنوعی داخل شهر عمل می کند. توسعه ی بی رویه شهرها و توجه نکردن به الگوهای توسعه ی فضایی مناسب باعث ایجاد ضعف در شکل و محتوای فضاهای ورودی شهرها شده و این فضاها را دچار مشکلات و نابه سامانی های متعدد کرده است. ممانعت از گسترش نابه سامانی در این عرصه ها مستلزم اتخاذ تدابیر ویژه و راه گشاست. هدف از این نوشتار، طراحی دوباره ی یک بخش فراموش شده شهری به شکلی تازه و با بیانی هماهنگ با نیازهای امروز، و نیز سامان دهی عملکردی ورودی شهر در ترکیبی درست است. در این پژوهش ابتدا مبادی ورودی)به عنوان یکی از فضاهای شهری(و مهم ترین کارکردهای آن تشریح شده، و سپس با توجه به معیارها و ضوابط عملیاتی به عوامل موثر در طراحی آن ها پرداخته و فضای ورودی شهر زنجان)مسیر آزادراه تهرانٓ زنجان(به صورت گرافیکی طراحی شده است.
کلیدواژگان: ورودی شهرها، کیفیت محیط مبادی ورودی، الگوهای سامان دهی، ضوابط بهسازی و نوسازی ورودی، طراحی ورودی شهر زنجان - یادداشت فنی
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صفحه 67دست یابی به اهداف اقتصادی در ایران سال 1404 نیازمند عوامل تولید از جمله «عامل انرژی» است. این عامل تاثیر گسترده یی بر اقتصاد دارد. به دلیل اهمیت گسترده ی انرژی در بخش حمل ونقل، پیش بینی تقاضای انرژی از مسائل مهم پیش رو در اقتصاد است. بنابراین لازم است برای پاسخ گویی به تقاضای آینده در بخش حمل ونقل، پیش بینی تقاضای انرژی در اولویت قرار گیرد.
در این مطالعه سعی شده با استفاده از مدل اقتصادسنجی خودتوضیح جمعی میانگین متحرک A R I M A(پانویس{a u t o r e g r e s s i v e i n t e g r a t e d m o v i n g a v e r a g e (A R I M A)}» در بازه زمانی 1346 تا 1388، تقاضای انرژی در بخش حمل ونقل ایران برای افق زمانی 1404 بررسی و پیش بینی شود. از نتایج این تحقیق می توان در ارائه ی پیشنهادهای سیاستی لازم در بخش عرضه ی انرژی برای پاسخ گویی به تقاضای انرژی در بخش حمل ونقل ایران استفاده ی بهینه کرد.
کلیدواژگان: تقاضای انرژی، پیش بینی تقاضای بخش حمل و نقل، مدل فرایند خودتوضیح جمعی میانگین متحرک (ARIMA) -
صفحه 73هزینه های مختلفی همچون آلودگی و تراکم موجب عدم شفافیت منافع احداث زیرساخت های حمل ونقلی و عدم کفایت هزینه های اولیه ی احداث به عنوان معیارهای اصلی مقایسه ی اقتصادی گزینه ها شده است. در این پژوهش با انجام یک مطالعه ی موردی، تعامل با چنین مشکلاتی بررسی شده است. آلودگی و تراکم به عنوان دو هزینه ی خارج از جیب معرفی شد و سه رویکرد «حفظ وضع موجود»، «احداث مسیر غیر هم سطح» و «احداث خط مترو» به عنوان گزینه های احتمالی تعامل با مشکلات ترافیکی وضع موجود معرفی شدند. نتایج حاصله بیان گر منافع 17درصدی)نسبت به کل هزینه ی احداث خط(ناشی از احداث خط مترو در سال افق طرح، بدون درنظر گرفتن ضرایب تعدیل بود. این مقدار برای گزینه ی تونل برابر 9درصد به دست آمد. ضمنا نتایج نشان دهنده ی این مهم بود که تصمیمات مبتنی بر هزینه های ساخت اولیه زیرساخت ها، بدون در نظر گرفتن منافع و هزینه های خارج از جیب آن ها، قابل ارزیابی صحیح نیست.
کلیدواژگان: تحلیل سود هزینه، هزینه های خارج از جیب، هزینه ی آلودگی، ارزش زمانی -
صفحه 83بخش حمل ونقل به عنوان یکی از عمده ترین مصرف کننده ی سوخت های فسیلی، نقشی اساسی در انتشار آلاینده های زیست محیطی دارد. این بخش در فرایند ارائه ی خدمات علاوه بر ستانده های مطلوب)جابه جایی بار و مسافر(،ستانده های نامطلوب)آلاینده های زیست محیطی(نیز ایجاد می کند. با توجه به نظریه ی پیگو، هر آلوده گر باید هزینه های آلایندگی خود را بپردازد، در این نوشتار با توجه به وجود کمبودها در زمینه ی روش های مناسب تحلیلی برای سیاست گذاری در زمینه ی محیط زیست، قیمت های سایه یی آلاینده های زیست محیطی که در اثر سوخت های فسیلی مصرف شده در بخش حمل ونقل منتشر می شوند، برآورد شده است. نتایج حاصله حاکی از آن است که قیمت سایه یی آلاینده های زیست محیطی که از مصرف هر لیتر بنزین و نفت گاز ایجاد می شود، به ترتیب 1039 ریال و 1075 ریال است.
کلیدواژگان: قیمت سایه، هزینه های خارجی، آلاینده های زیست محیطی، سوخت های فسیلی حمل و نقل -
صفحه 93تصادفات مربوط به پیاده دانش آموز به دلیل عدم آگاهی و آشنایی نسبت به خطرات ترافیکی در اطراف مدرسه و همچنین مسیرهای مدرسه تا منزل باعث شده است تا این گروه از کاربران راه ها خصوصا دانش آموزانی که در مدارس حاشیه ی جاده های اصلی مشغول به تحصیل اند بیشتر از دیگر کاربران جاده یی در معرض خطر قرار گیرند و در زمره ی گروه های آسیب پذیر در حوادث جاده یی به شمار روند.مرجع{1} بر این اساس طرح آموزش ایمنی عبور و مرور و ایمن سازی مدارس حاشیه ی راه ها در یک دوره ی هشت ساله و با استفاده از روش ها و شیوه های علمی و عملی مصاحبه، پرسش نامه و شاخص های کمی و کیفی مورد ارزیابی قرار گرفت. نتایج حاصله نشان داد در سال های اجرای طرح که تعداد دانش آموزان حدود 1٫5 میلیون بوده و 8 میلیون نفر ساعت فعالیت آموزشی انجام شده است، میانگین نمرات دانش آموزان در آزمون اولیه از 3 به 14 و در آزمون نهایی از 14 به 17٫5)طی سال های 1384 تا 1388(ارتقا یافته است. همچنین در سال های یادشده تعداد تلفات دانش آموزان در محدوده ی مدارس از 1987 نفر به 598 نفر رسیده که معادل 70درصد کاهش داشته و در محدوده ی خارج از مدارس نیز از 2734 نفر به 1257 نفر)معادل 54درصد(مرجع{2} کاهش یافته است.
کلیدواژگان: آموزش ترافیک، فرهنگ ترافیک، ایمنی عبور و مرور دانش آموزان
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Page 3In this article, we study and estimate the direct and indirect impacts of the rise in energy prices on the transportation sector of Iran, using IO and SAM models. We also examine the impacts of new energy prices on urban transportation and the welfare of urban households. The findings of our study are as ollows:1. ransportation costs will increase dramatically: firstly, the SAM model shows higher cost increases compared with the IO model. Secondly, under the IO model, water and air transportation show the highest cost rise, while, under the SAM model, it is air and road transportation that face the highest cost rise. Regarding the importance of transportation for economic activities and the welfare of citizens, it was expected that the government would have a comprehensive and transparent policy for the renovation of all modes of transportation and would provide enough subsidies for this purpose. Unfortunately, this expectation has not been realized so far.2. The cost of using private cars will increase 195%, and the cost of public transportation will rise 48.6%. Due to this fact, households will use less cars and more public transportation in the short run. They will also try to replace their old cars in the long run. But the government policies do not facilitate the expansion of public urban transportation and the renovation of private cars. The government has reduced its transfer payments to municipalities for the development and renovation of public urban transportation in recent years, and, with its unconditional and high protection of the local car industry for a long period, has increased car prices in the national market, hindering the renovation of the car fleet.3. This study shows that the government policy to pay cash subsidies to households will only compensate the welfare losses of the two lowest deciles of income. Since this policy does not cover the losses of 40 percent of the population who are among the poor, it does not conform to the aims of the social justice policy of the government.Keywords: energy Price, cost of transportation, direct impact on cost of production, indirect impact on cost of production, welfare effects
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Page 17Urban sustainable development requires effective and efficient management strategies that employ invaluable and scarce resources appropriately. Such approaches to the transportation and traffic problem include an innovative definition of the problem, mainly based on more efficient traffic management strategies. Considering the derived nature of transportation demand, these transportation demand management (TDM) strategies make possible the achievement of a trip purpose without need of the actual trip, which, in cases of educational trips, can be materialized by, e.g., distance-learning. This paper aims for an economic impact analysis of distance-learning as a TDM strategy for educational trips in the city of Mashhad, through scenario building for the morning traffic peak period.Due to the scarcity of research in the field of distance-learning and its impact analysis, particularly in Iran, this paper is a first effort in addressing this issue; particularly from a quantitative perspective. Comprehensive transportation studies of the city of Mashad are utilized as the basis for data and information needed to run the models on the scale of a large city with a population of more than 2.5 million. The software package used for transportation modeling and calculation of the impact of different scenarios of distance-learning adoption, is VISUM; yielding total vehicle-kilometers traveled (VKT). Wardrop's first principal of equilibrium is used as the conceptual framework for the prediction of link volumes; given the network structure, link performance functions and origin destination demand matrices.Results of the twenty-one scenario model implementations show that the economic savings due to these scenarios range from 1.5 to 2.5 million VKT, which, for the 50 percent adoption scenario, is about 2.06, causing a saving in gas consumption of about 47 thousand liters. Assuming the price of 7000 rials per liter, approximately 33 million rials can be saved by applying this strategy for one hour of morning peak traffic. Results of this paper can be useful to urban managers in planning transportation systems, and the alleviation of the traffic problem of large and opulated cities, by omitting trips whose purpose can be attained otherwise, through the application of nformation and communication technology.Keywords: sustainable economic development, distance, learning, transportation demand
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Page 23Congestion, when driving a car, is a common problem for megalopolis citizens because it imposes environmental and social costs, such as air and noise pollution, depletion of energy, road casualties and daily delays. Because of limitations on expanding transportation networks, over the past several decades, policymakers and transportation planners around the world have attempted to reduce congestion by proposing transportation demand management (TDM) policies. Today, the integration of TDM policies as a realistic and effective approach is a challengeable issue in urban policy studies. In fact, interaction between policies that are not addressed broadly in an integration context plays a main role in the outcome of TDM policy packages. On the other hand, different individual aims in daily trips, city development, variation of land use, and different levels of decision making in transportation, often leads to implementation of more than one TDM policy at a time. This study examines the role of TDM policy packages on commuter mode choice in the city of Tehran. The analysis is based on the results of a stated preference survey developed by efficient designers, as a specialized design type of experimental approach, which allows assessing all two-way interactions of policies, as well as their main effects. Five policies consist of increasing parking cost, increasing fuel cost, cordon pricing, transit time reduction and transit access improvement are assessed when considering six modes of transport to the work place. A multinomial logit model was developed for 366 commuters who regularly go to their workplace in the centre of the city. In addition to a number of commuting and contextual variables, the model shows that the policie's main effect and their interactions are significant in mode choice, and are effective. The results show that for car users who faced TDM policies, all five studied TDM policies were factors in the mode choice process. The model shows that in considering car usage, push policies play a main role, and pull policies do not. Results of the model also show that to implement a single policy, cordon pricing is the most effective in decreasing car usage. The marginal values of policies are also presented, and three graphs are provided to show the results of the implementation of the model.Keywords: transportation demand management, policy package, car use, mode choice, logit model
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Page 33In recent years, ample attention has been paid to the use of BRT in Tehran. Development of such systems is in need of proper assessment of effectiveness on air pollution reduction, as well as traffic. In the resent nvestigation, the role of BRT on the environment and socio-economic aspects has been assessed in the route between Parkway and Tajrish square. The research has been carried out at two stages of pre and post utilization, and is truly based on field measurements as well as questionnaires. Results of the present investigation showed that the most prominent effect is on social aspects, due to the reduction in social costs that occurs due to the lower emission of air pollutants, as well as lower fuel consumption. The profits of this cost reduction can be used in corrective measures, such as the construction of sound barriers.To evaluate the effects of BRT, we have tried to assess such effects on the physical, biological, social, economical and cultural environment. It should be noted that the highest adverse impact is found on the physical environment, which arises from air quality, as well as noise pollution. The adverse effects on the biological environment are too minimal and insignificant, since there are virtually no important biological units in the area of study. The highest positive impact of BRT can be seen on the social environment, which is mainly associated with elements such as safety and hygiene. In general, the results of the environmental impact assessment (EIA) are indicative of the positive effects of BRT on various environments, along with the route, in the area of study.It is interesting to note that external costs, including social and environmental costs, were reduced by about US$ 165000 per year. The reduction in gasoil consumption is around 682 thousand liters per year, with a value of US$ 434000. The result of the present investigation clearly shows that the benefits and effectiveness of BRT can further be promoted by some simple measures. These include a reduction of noise along the roadside using appropriate barriers. The increase in the number of buses, along with better hygiene aspects, will lead to more convenience for passengers. There is no doubt that the satisfaction of shopkeepers can be achieved by provision of some reduction in taxes or a reduction in the price of energy or water bills. Though the lower income population has a better reason for using BRT, it should be noted that about %13 of BRT's passengers are those who have preferred to leave aside their personal cars once the BRT line has been fully in operation.Keywords: transport, pollution, BRT, fuel, social cost, environment
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Page 41Urban transportation and traffic has become a major problem for all citizens, particularly in metropolitan areas. Improving the urban transport infrastructure, regarding the growth of population and the private fleet, seems no longer adequate. Therefore, transportation demand management has become of great importance in recent years. The purpose of this paper is to compare fuel consumption management strategies in urban transport, in Iran, based on a quantitative scoring methodology.Thus, first, strategies for managing fuel consumption in urban transport (13 titles) and policies for each strategy (44 cases) in 14 countries are identified and classified in three groups (fleet, transportation management, and fuel). Then, policies are scored and prioritized, employing the ideal point methodology (Minkawsky distance analysis), results of which show that the top 3 strategies are: the development of public transit (especially rail), the expansion of intelligent transportation systems (ITS) and energy sources development.With this distance analysis, all 44 policies evaluated are classified into 27 equivalent categories. The four top policies are: expanding the public network, developing and applying ITS and traffic control and management for reducing congestion and fuel consumption, improving access to public transport and its services, and development and investment in renewable energies (solar, bio,. ..). The results of this study seem to be highly consistent with expertise arbitrations and can be considered with good credit.Comparing the prioritization output with current policies in Iranian metropolises shows that the only common strategy is to develop public transport, and its two subset policies (expanding the public network and Government subsidies to public transport systems). Other superior suggested alternatives are neglected, which can be due to incorrect, or at least incomplete, problem definition.Keywords: fuel consumption management, urban transportation, fuel economy strategies, policy prioritization, ideal point method
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Page 53The entrance space of a city acts as an urban space; a joint linking of natural space outside to artificial space inside. The illogical and unscheduled development of cities, as well as the lack of concern for suitable space development paradigms, has brought about weaknesses in the form and content of the entrance spaces of cities in Iran. This has caused numerous and various problems and disorders, which necessitate taking special, ground-breaking measures.These ravages have been so epidemic that these fields cannot even meet the minimum requirements to becalled as an urban area. The precipitous expanding of these ravages in these fields, which, in the future, will be the inner components of the city, represents the importance of the subject.Since the entrance space in cities and urban areas is considered one of the first spaces in the city to deal with the problem, given the input patterns in the spatial relationship between these subjects considered in urban areas are most basic challenges to be dealt with.To achieve the appropriate solutions in planning and organizing the entrance boulevards of the cities, at first we should consider the nature of entrances and know them then regard the characteristics of them.By evaluating of the changes of Entrance Boulevard of cities up to now, we can catch the social, cultural, political, economic and technological evolutions.Over time, the patterns of biological communities in settlements of the land are affected. Spaces, and the entrance gate into the old town, fort defined coordinates, entry to corridors with scattered, ugly, worn out and worthless residential buildings, and abandoned spaces, show disturbing reports of the uncontrolled growth and development of modern cities. A city's growth and beginnings or, in other words, definitions of the limits for a city, are irrelevant and meaningless.The present article tries to designate and reform a long forgotten urban sector in a new form, taking into account current needs and the functional organization of the entrances to cities in an appropriate way, to satisfy the needs emerging upon entering the cities. In this research, we have first identified and introduced the entrance as one of the urban spaces, as well as one of the important functions of entrance gates, causing consequential problems. Then, we have identified the factors affecting the design of city entrances. Considering the entrance to a contemporary city and the expectations at the main points of entry, and the ravages of the functions it has to grapple with, proper attention is paid to the obtained results. Considering functional regulations and criteria, as well as the entrance space of Zanjan (Tehran- Zanjan Express way), we have graphically designed these factors.Keywords: city entrance spaces, environmental quality of entrance gates to metropolitan cities, disorders of the environmental quality, regulations and criteria
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Page 67The transport sector is vital to the economy of each country. Thus, this sector affects main economic variables, such as production, employment and the cost of living index in the short and long terms. Transportation is considered a key component of the national economy and infrastructure, due to the impact of the economic growth process. Apart from the important role of transportation in the service sector, it is also a main element in other economic sectors, such as agriculture and industry. Transport plays a role in the consumption market, as a bridge across various sectors of society, to move towards sustainable development. Given the importance of transport in the economic growth and prosperity of Iran, the study and identification of factors that affect this development are very important. Energy, as an important factor of production, as well as of the final products, has very important role, with significant effects on various sectors of the economy, especially the transportation sector. Transport is a major consumer of energy, and transportation vehicles use many forms of hydrocarbon fuel.Although in Iran, because of energy fluency and energy resource diversification, prices for domestic consumers are low, due to the need to understand the possible end of these God-given resources and prevent the crises of energy demand in the future, examination of the determinants of energy demand is important. The achievement of planned targets for the Iranian economy, Iran's prospects in 1404, requires readiness in a variety of areas, including resources and factors of production.Because of the importance of energy in the transportation sector, the prediction of energy demand is a major problem facing the economy. Therefore,forecasting energy demands, to respond to future demand in the transportation sector, is a priority for the economy.This study forecasts energy demand in the transportation sector in Iran, from 1346 to 1388, for the 1404 time horizon, using an econometric model named, `ARIMA'. The study results that estimate the rate of energy demand in this sector can provide the necessary policy proposals on energy supply in response to energy demand in the transportation sector in Iran.Keywords: energy demand, demand forecast, transportation, ARIMA models
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Page 73Investment and construction of transportation infrastructures are some of the most complex issues that confront governmental authorities. Uncertainty in the benefits of such infrastructures and, also, difficulty in scaling costs to financial profits, create doubts in the decision making process. Congestion pollution, noise and other issues have significant costs and, therefore, the initial cost of the infrastructure cannot be a proper comparison factor for its economical study. Therefore, it seems necessary to analyze the demand in the horizon year, considering the current situation and using the outcome of planning studies. Evaluating construction and operation costs next to the project profits then leads to applicable decisions. The research aims to study the solution in a particular route case; Sadr expressway in Tehran, which is the sole arterial road to connect the north and north-east of Tehran City to its central region. Studies in the horizon year show that there will be a 104 percent increase of total delay on this expressway in a no action scenario.Pollution and congestion are studied as direct costs of the project, and three alternatives, i.e. maintaining current conditions, a grade separated route (tunnel, in this case) and a metro line along Sadr expressway, are considered as direct cost mitigation solutions for this expressway. The results suggest that direct costs, due to congestion and pollution, are so significant that the profits of the metro line in the horizon year made 17% of the total cost. However, considering discount rates, profits for the tunnel alternative is only 9% of the whole cost. In addition, it is concluded that decisions made on just capital costs (without counting for profits) may not be evaluated properly. The metro alternative, though having higher capital cost in comparison to the tunnel alternative, looks more economical in the long term, due to its quicker investment return time. Moreover, it was shown that, in some cases, choosing the no action alternative can be even better than constructing an infrastructure. The pollution cost in the tunnel alternative was estimated as being more than the no action alternative, due to the induced traffic when constructing a new infrastructure.Keywords: cost benefit analysis, out of pocket costs, pollution costs, value of time
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Page 83To scientists of the natural sciences, in general, and to those of the environmental sciences, in particular, pollution is waste, resulted from economic activities and disposed into the environment. In other words,pollution is the result of an incomplete production/consumption process, wherein production elements are made into a product. Pollution can be divided into two main groups, namely ``flow pollution'' and ``stock pollution''. Flow pollution occurs when the damage (loss) is related to the ``amount'' of emission. In other words, emission of the pollutants into the environment happens with the passage of time. In this kind of pollution, if the flow stops, the related costs tend to zero immediately. The damage (loss) of this kind of pollution at any time depends on its present rate of emission. In stock pollution, the damage (loss) is a function of the amount of pollutants stocked in the environmental system at any time. The loss (damage) due to the pollutants stocked in the environment is more than that of those in nature.The transportation sector, being a main consumer of fossil fuels, plays a basic role in the emission of environmental pollutants. In the process of giving service, this sector creates undesirable outputs (environmental pollutants), in addition to desirable ones (cargo and passenger transfer). Considering the Pigo theory, which says that every polluter should pay the cost of his polluting behavior, and also the scarcity of appropriate analytical methods for the purpose of environmental policy making, an effort has been made, in this paper, to estimate shadow prices or final external costs of environmental pollutants created by fossil fuel consumption in the transportation sector. Results have revealed that the shadow prices of environmental pollutants per liter of consumed gas or gasoil, are 1039 and 1075 Rials, respectively. Therefore, based on Pigo's theory (a polluter should pay for his pollution), it is suggested that the compensation taken from the polluter be based on the shadow prices estimated in the present research, so that it can offset the damage (loss). In this study, the shadow price of all environmental pollutants caused by gas and gasoil consumed in the transportation sector has been estimated as a whole. Therefore, it is suggested that these pollutant's shadow prices be calculated separately (in other research), so that a comparison between them becomes possible.Keywords: shadow price, external costs, environmental pollutants, transportation fossil fuels
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Page 93Road safety is one of the most essential concerns in developing countries, where the majority of road fatalities are from road accidents. Because of the vulnerability of children in road crashes, they are at the centre of plans utilized towards road safety. International agencies place a great emphasis on child health, and road safety is considered important. It is believed that children need to be more careful, regarding their abilities and knowledge. Training and education are the most important parts of child safety, and evaluation is the final process of executing training plans.To decrease the number of student fatalities, a comprehensive plan of child road safety, which focuses on children whose schools are located near rural roads, has been implemented. An improving road safety plan, including training, physical measures and dissemination of educational matters to students and their parents, has been undertaken throughout Iran. In this paper, the effectiveness of annual education programs has been studied on improving child safety, for those whose schools are located near rural roads.An official methodology of the education process, including cultural and constructive measures, has been introduced to improve children's abilities regarding hazard diagnosis and safety skills. Constructive measures include road signs that indicate drivers to be aware when they are close to rural schools, and some low cost measures, such as dividing the routes of pedestrians and cars.Child fatalities and knowledge scores are considered as comparison measures, based on hospital statistics, using before and after implementation. Considering student knowledge improvement, a number of children have been analyzed, and results reveal that the effects of annual education programs have significant effects on child safety. Statistical measures based on hospital data, show that the number of fatalities regarding school children, decreased from 4721 to 1288 during the six year time study; from 2004 to 2010.Keywords: road safety, school children, education program, social concern, cultural and physical measures
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