نشریه مهندسی ترافیک
پیاپی 44 (پاییز 1389)

To design path corridor based on construction cost, designers mainly notice to geometricaldesign factors and primary construction cost, while some other effectivefactors may be ignored. Environmental condition is another effective factor thathas a significant effect on recognition, selection and determination of path corridor.Examination of all environmental parameters is very important and if they can beprocessed simultaneously with other effective factors, many useful results will beextracted for optimum design. According to the proposed model in this study, asite in frame of GIS system was considered regarding to frequency of informationlayers and effective factors on recognition and determination of path corridor. Allgraphical maps and descriptive information for the site between two path ends wasentered as separate layers, and each layer was weighted proportional to its effectin decision-making, and money value is assigned to their components. Then alldescriptive and graphical information are classified by the software and processedby mathematical analytical methods and will be modified to cost map or total effectivevalue. Then a vector network is constructed onto this map by software, andinformation on cost map is transferred to the vector network upon view of designer.Finally, the best and the cheapest path is selected by the software upon differentalgorithms. This method increases precision of recognition of optimum variant orderly,introduces all possible variants in details, decreases evaluation time of variantsand cost significantly.

Measuring and monitoring the air is inevitable for investigating the air of surroundingenvironment and learning about the rate and density of the harmful effects of pollutionson the environment and humans` health. Air monitoring is an essential managingtool to monitor the air and reduce its pollution. The correct pollution management ispossible when reliable database of air qualitative status is available. To investigatethe role of different factors such as urban traffic on accumulation of air suspendedparticles, the particles` density at Navab Highway and Azadi St. were measuredin different crossroads and different circumstances. Two stations were selected ateach highway and suspended particles with PM1, PM2.5 and PM10 sizes as themajor pollutions were measured in summer, fall, winter and spring of 2009-2010at 1.8m and 5m from earth surface breathing heights. At the same time the sameparameters were measured to study the changes in suspended particles densitydue to wind speed and number of passing automobiles. The results showed thatthe more the automobiles pass the highway the more the density of suspendedparticles especially PM10 will be. The increase of wind speed will also result inthe increase of all three sizes of particles in mentioned highways. Meanwhile, thetotal average of suspended particles` density of PM1, PM2.5 and PM10 at NavabHighway has been upper than Azadi St. due to its south to north structure whichavoids cleaning effect of dominant western winds of Tehran city.

Most of the large cities of the world are encountered with the problems of increaseduse of personal vehicles and also decreased quality of lifeand accessibility. Theencouragement of people to use public transportation as a unique, regular andintegrate set may lead improvement of the quality oflife and accessibility in compareto the other door to doortrips by the personal vehicles. This paper has triedto examine theprincipals of integration of transportation, integration process in thetransportation industry, which finally all of these cases and process will providetheurban transportation efficiency.

Provide an appropriate method to locate optimal urban bus stations in transportationnetwork is the principle aim of this study. In this study after determining thepoints of demand, identify candidate locations and locate p facilities with minimalcost in the network.In this paper a new formulation for the p-median problembased on two types of decision variables and with only linear equality constraintsis presented, where is the number of demand points or customers and is thenumber of facilities. Then for solving the problem, is proposed hybrid algorithmconsists of genetic algorithm and competitive recurrent neural network.In this method instead of the reproduction operator of genetic algorithm, competitiverecurrent neural network will use. Competitive recurrent neural network structureconsists of location layer related to decision variables and allocation layer relatedto decision variables. The process units constitute disjoint groups, where only oneprocess unit per group is active at the same time. In addition, the network energyfunction that is equivalent fitness function of genetic algorithm always decreases orremains constant according to the dynamical rule proposed. The effectiveness andefficiency of this algorithm for standard problems is analyzed. The results indicatethat the proposed algorithm generates fine quality and acceptable solutions.

As we know, the most effective of traffic facilities on the drivers behavior and giving right of way in cities, is traffic signals. The countdown signals are used for simplifying in decision making at intersections. This research has focused on countdown signals operations. Countdown signals in Iran are displayed remained green and red time based on previous cycle and by the reason of changing in cycle length sequences in actuated signals has encountered with some problems so. This research evaluate countdown signals operation and problems based on interview of Iranian drivers.

Nowadays the use of roundabouts due to reduce delay time, stops delay and landscaping is more common and take place of signalized intersections. But it must have strong justifications (e.g. do not locating a roundabout for oversaturated intersections). Totally some roundabouts due to geometric design and several entries and exits should be improved besides traffic analysis. In this research a method to revise abnormal roundabouts with more than ten entries - exits will be presented. Finally a case study will be surveyed. In this case which has abnormal geometric design and heavy traffic at peak hours a methodology for these king of roundabouts will be presented.

One important issue in transportation planning is the estimation of network link andpath flows, as outputs of traffic assignment process. Different methods of traffic assignment are based on different assumptions, mainly the behavioral assumption.Incremental assignment is one of the heuristic methods to estimate the equilibriumflow pattern, which although unable to produce the exact results similar to observations,is quite efficient due to its simplicity and amount of computation. An important criterion in this method, specifying the amount of calculation is the number of iterations. In this paper, the effect of the number of iterations on the accuracy of results is analyzed and computed for different iterations (2 to 12) for Mashad City, using VISUM software package. Results based on the comparison of model results with observations, indicate that increasing the number of iterations up to a certain threshold causes model outputs to replicate observations more accurately.However, beyond that threshold, coefficient of determination shows an asymptoticbehavior, so that further increase in iteration number does not affect the resultsnoticeably. The threshold for the case of this research was shown to be eight iterations.