نشریه مهندسی ترافیک
پیاپی 72 (بهار 1397)

Traffic accidents are one of the very important factors of mortality and morbidity and is severely threatened human society by the severe effects of social, cultural and economic. The damage was more severe in developing countries, such as Iran and therefore the number and severity of accidents in these countries is several times higher compared with developed countries. Basically, the cost of accidents consist of two main parts: internal and external costs that external costs consist of the price of human lives and economic impacts of disabilities and mental injuries. In this study, according to collecting the statistics of death, injury and damage accidents of region 2 roads in Tehran city in 1393, part of the external costs include the cost of death and disability is estimated. To quantify the effects of the accident on human health and mortality, is used the DALY indicator that this indicator is used for assessment of human health (with the economic perspective of cost-benefit) and is unique quantitative indicator that is used for assess the external cost of death, desease or disability and is representative of the adjusted life year due to premature death to disability. Also in this study, it is tried first, separately collecting the statistics of accidents of region 2 roads in Tehran city then the roads have death accidents isolated and disability Adjusted Life Year (DALY indicator) has to be calculated for roads that have death accidents.

Weaving segments exist where two significant traffic streams cross each other’s path at grade over a length of highway. The weaving maneuvers intending to perform lane changes in these segments cause a level of turbulence in the traffic flow. The turbulence leads to extensive speed changes, the reduction of the level of service and the safety in these segments. Therefore, this study, which has used the actual lane-changing rate, attempts to evaluate the performance of the model that was proposed in the fifth edition of Highway Capacity Manual (HCM 2010) and its calibrated model based on Tehran highways. Thereby, the field-data was collected on the ramp-weaving segment of a freeway in Isfahan, using a closed circuit observation technique. The procedure was of 7 fifteen-minute time steps of recording at different hours of a working day. The findings in this study show the weakness of the HCM 2010 in the lane-changing rate estimation (especially non-weaving flow) in the way that it under-predicts the rates in all cases and the calibrated model could only adjust it in prediction of non-weaving lane-changing rate. Even the calibrated model has negatively affected the HCM 2010 in estimation of weaving lane-changing rate.

Nowadays with the increase of transportation demand and according to the fact that there is a limit to financial budget to optimally assign to transportation infrastructure, safety is considered as a crucial issue faced by transport experts and also the people. One of the short time solutions to enhance safety level is to attend to drivers’ behavior in road selection. In other words, road users are usually forced to select. According to the development of multi attribute decision making methods, it is possible to assess complex problems. However, in actual fact, much more problems are introduced in uncertainty environment. In the other words, experts’ judgments are often incomplete and unreliable. In such situations, the present MADM methods are not able to evaluate. So, the present research study aims at introduce a novel method dealing with uncertain conditions namely Evidential reasoning (ER) approach, and assess the roads located in the north of Iran including Haraz, Firouzkuh, Kandwan, and Kiasar in terms of safety.

Using appropriate variables that can consider individual, family and trip attribute effects on transportation decision is known as one of the most important part of transportation modeling. The goal of this study is using life cycle variables to have more accurate describing of family structure. For example life cycle can discriminate between families with similar number of children and adult but different children’s age, adult’s age and employment status and this discrimination will bring more accuracy for family attribute. This study use life cycle variables in trip mode choice modeling for different trips purpose. One of the most important results of this paper is substantial rule of life cycle variables compared with household size variable in educational, social-recreational and personal trips.

Nowadays collison warning systems are based on sharing position data between vehicles. The most common solution is using Dedicated Short Range Communication(DSRC). But this technology has met a lot of limitations. The spread of cellular network technology and it’s wide area coverage can make cellular network a proper alternative for DSRC. In this paper,first the collision senarios have been reviewed and their use cases are specified. It has been showed that 100 msec time delay is not essential in all collision senarios. Then 3G and 4G/LTE are evaluated for using as the main network in connected vehicles. The results show that 4G/LTE has the proper potential for using in vehicular network instead of DSRC. The time delay in 4G/LTE was below 100 msec in 98.14 per cent of samples. Also 3G had the mean time delay of 250 msec and can only be used in senarios that the vehicle’s speed are low and the distance between vehicles is high.

Urban street network is vulnerable in the sense that may be impaired as a result of various factors. This disorder may significantly affect movement in some parts of the city. In order to analyze the vulnerability of street network and efforts to reduce it, that is necessary to define the criterion for evaluation and priority of transportation projects and to set criteria to be added. Connective criterion, a new one, that enhances the reliability and stability of the overall urban street network. As a result, resistance against blocking part of the road network increases. Connective criterion makes effective connections increase and urban street network to be interconnected together. In this research, existing criteria and connective ones have been studied and five scenarios in Esfahan based on existing standards and again with the addition of new criterion are prioritized. The purpose isn’t the change of the valuation method but it is to add new criterion. The results show that priorities will be changed with the addition of connective criterion. Therefore, it is important to pay attention to it.

Air pollution is among the most concerning challenges in metropolises. A significant part of this pollution is in regard to transportation. Some transportation projects, like highway construction or street widening projects would encourage the citizens to use their private cars instead of public transportation which will lead to more emissions of contaminants. In most cases, estimation of transportation projects by cost-benefit analyzing will lead to an underestimation of destroying effects. The transportation fleet is the major source of pollutants in cities. Bus Rapid Transit (BRT) lines which are considered as an index of sustainable transportation, has been built in Tehran metropolitan areas recently. In this study, the evaluation of transportation projects with respect to sustainable transportation criteria in urban areas has been taken into account and also environmental effects of transportation projects have been measured. This paper reviews Tehran BRT Line 4 in order to evaluate the effect of exclusive lane of BRT on Chamran highway’s amount of air pollutants. For this purpose the amount of emitted pollutants in BRT line 4, are compared based on the traffic volume information. This modeling includes two scenarios: before and after the construction of BRT Lines. Comparison of modeling results would clarify the effect of BRT lines on reduction of the amount of air pollutants.

Aberrant behaviours of pedestrians have been subject of very limited studies in the country. International studies are also mainly limited to social cognition theories (particularly theory of planned behaviour) and road users other than pedestrians. The present study aims to investigate differences in walking aberrant behaviours (attention violation, transgression and aggressive behaviours) among males and females, considering behavioural precursors of safety attitudes and cultural variables. A sample of respondents (N=293) from Tehran and Karaj with average 37.6 year old (SD=16.7) including males (51.9%) and females (48.1%) responded to a questionnaire composed of cultural, attitudinal and behavioural instruments. Exploratory and confirmatory factor analyses were conducted to draw the structure of latent variables. Structural equation modeling was used to determine the causative relations between the variables. Results showed that while the all factors (except transgression) are not statistically significant among male and female groups (p<0.05), The behavioural structures are different in males and females. According to this structure, Collectivism (horizontal and vertical) (B=0.331, p<0.001) and vertical individualism (B=0.315, p<0.001) improve the safety attitudes in females. Furthermore, effect of safety attitudes on behaviour is stronger in males (B=-0.837) than in females (B=-0.730). The paper discusses the implications of results.