جستجوی مقالات مرتبط با کلیدواژه « جاده های کوهستانی » در نشریات گروه « فنی و مهندسی »

In developing countries, the crash risk on mountainous rural highways is higher than on non-mountainous rural highways due to their complex geometric design. Thus, the consistency of geometric characteristics with drivers’ behavior plays a remarkable role in reducing crashes in these areas. In this study, two substandard mountainous rural highways of Iran were selected to measure local design consistency based on continuous speed data collected by smartphone technology. The idea of employing critical elements was introduced to evaluate local design consistency. The critical element is an individual element with a higher CCR (curvature change rate) value compared to the CCR values of their adjacent elements. An individual element was defined as a curve or a group of curves with similar CCR values, and short tangents between each two curves. The efficiency of this concept was evaluated base on statistical hypothesis test and determining spearman rank coefficient between a popular design consistency indictor and expected rural highway crashes. The null hypothesis was rejected for all of the critical elements and it was confirmed that drivers reduce their speed when they face the critical element. Finally, several concepts related to design consistency on mountainous rural highways were elaborated according to operating speed profiles.

Avalanches are of highly probable natural disasters on mountain roads during cold seasons. This natural phenomenon is also a usual reason of road closures and casualties in Iran especially in roads between Tehran and northern cities and western and north-western roads. In order to preventing or reducing avalanche incidents, first, more risky points should be identified and next, suitable safety actions must be considered. Previous studies mainly use regional and geological data based on field inspections, whereas, several other parameters are considered in this study and a combined model is developed. The parameters are snow depth, side slope, vegetation, avalanche frequency, vehicle collision possibility, daily traffic count, and expert interview. Ten avalanche-prone points are identified in Karaj-Chalous road and are prioritized using method of TOPSIS. The results show that avalanche frequency is the most effective factor. Moreover, the results show that sections of 62퍍63퍍, 63퍍68퍍, and 70퍍74퍍 are the most risky ones and safety solutions should be considered in these points.

Falling avalanche is one of incidents that may happen during cold months of winter in Iran. This event may lead to closure of some main roads of the country. Road closure is a challenging issue، particularly on roads connecting Tehran capital to the northern cities. Detecting avalanche prone locations on roads is usually conducted by data gathering، surveying and investigating aerial photos. Field investigation usually requires collecting regional data including slope stability، geology and number and repetition of road traffic. In this study importance of each parameter was determined By an AHP method. After interviewing experts، importance of each parameter was determined pair wise. Final weights for each parameter were also determined using Expert Choice software. Searching for important contributing parameters and methods for measuring risk of avalanche in mountainous roads in the literature، main parameters of falling avalanche were selected and used in this study. It is obvious that many of recognized parameters should be considered in every effort of measuring danger. That is why such parameters are similarly used in most methods. The most important reference for categorizing the methods of risk measuring was guidelines on preventing falling stones and avalanche published by US National Institute of Highways and the Main Office of Highways. In these guidelines، traffic repetition is taken as an important factor increasing the risk after a falling event happens. This study framed the experts’ opinions and optimized risk analysis with regards to local geotechnical and geologic conditions in Iran. Experts selected the snow depth، hillside slope، vegetation condition on hillside and number and repetition of the road traffic. Importance of parameters were calculated as 44. 1% for traffic number and repetition، 19. 1% for the hillside slope، 17. 2% for vegetation، 15. 6% for snow depth and 4% for traffic rate. These parameters were selected as the factors contributing in avalanche. In continue each parameter was rated in a four level category (very high، high، medium and low). Model of avalanche danger calculates the avalanche risk in every point in a road network and all roads can be evaluated in terms of the danger of potential avalanche. For example the model was applied on Karaj-Chalus highway connecting Alborz to Mazandaran provinces. This highway is an important arterial between the capital and the northern cities. Using the method، 15 dangerous avalanche prone locations were determined and prioritized. They are located at 65، 73 and 60 km from Karaj. Preventive efforts should be taken for maintaining these locations and keeping them safe against potential avalanches