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Since a significant percentage of crashes occur at black spots, different methods have been proposed to prioritize the modification of these spots and prevent crashes. One of these prevention methods in transportation is the hazard warning systems. The purpose of this study is to evaluate the satisfaction of drivers and their affectability from a map-based warning application is evaluated. To this end, black spots were identified on one of the two-way two-lane highways in the North-West of Iran and 32 male drivers were tested in the intervention group (warning state) and the control group (non-warning state). The evaluation of the warning application was done in two steps. In the first stage, drivers’ affectability between the two groups was compared, where average speed and number of speed limit violations were studied in warning and non-warning states. In the second stage, drivers' satisfaction with application features was examined using questionnaires. The findings showed that the difference in mean speeds at black spots between warning and non-warning states was significant with 95% confidence level and the use of warning application was effective in reducing the number of drivers with speed limit violations at black spots. Most drivers were highly content with the warning from car speakers, advisory warnings and warning distance from black spot, and did not have enough satisfaction with visual warnings, the application installation procedure, and warnings from smartphone speakers. Additionally, the results of the questionnaire revealed that not only warnings did not cause distraction for the drivers, they were effective in increasing their caution. These findings can be used to eliminate the shortcomings of the hazard warning application.

Rollover crash is a type of dangerous crash that occurs often in two-lane highways. Therefore, this study evaluates the effect of road shoulder and weather condition on rollover crashes. Crash data show that 8,609 crashes were recorded from 2006 to 2009 on six two-lane highways located at the center of Iran. This data contains 1860 rollover crashes. Rollover crash in this paper not included the head on crashes and fixed object crashes. Therefore the rollover crashes are only single vehicle crashes. Binary logit was selected for modelling since there were two possible outcomes: rollover crashes and other crash types. The variables of the final model include highway class, road shoulder width, as well as rainy, snowy, foggy and night conditions. The modeling results show that rainy and foggy variables, with coefficients of 0.731 and 0.719 respectively, had the greatest effects on rollover crash occurrence. Also, road shoulder width and night conditions, with coefficients of 0.221 and 0.184 respectively, had the least effects on rollover crash occurrence. Afterward, sensitivity analysis was performed on all the independent variables, and the results show variable variation and indicate that the probability of rollover crash occurrence is 21.29 % on the mentioned highway.

Traffic crashes are a social problem around the world and climate change is one of the major environmental factors that cause road crashes. The severity of multi-vehicle crashes under different weather conditions was investigated in this study. Crash data for three levels of crash severity (i.e. crashes involving property damage only (PDO), injury or fatality) from six highways in Iran were evaluated. Ordered logit models were selected for the analysis because of the ordinal nature of crash severity. The final model consists of seven independent variables: temperature below −7°C, temperature above 19°C, rainfall exceeding 5 mm/d, working day of the week, density (vehicles/km), roadside equipment and season of the year. These variables were found to have significant values at 0·95 confidence intervals. The model also showed that the probability of occurrence of a PDO crash is 77·5%, while the probability of occurrence of injury and fatal crashes are 18·9% and 3·6%, respectively.

Background Road traffic crashes (RTCs) and its associated injuries are one of the most important public health problems in the world. In Iran, RTCs rank second in terms of mortality. To address this issue, there is a need for research-based interventions. Prioritizing researches using a variety of approaches and frameworks to determine the most effective interventions is a key nodal point in the RTCs' research policy planning cycle. Thus, this study aims to generate and prioritize research questions in the field of RTCs in Iran. Methods By adapting the Child Health and Nutrition Research Initiative (CHNRI) method, this study engaged 25 prominent Iranian academic leaders having role in setting Iran’s long-term road safety goals, a group of research funders, and policymakers. The experts' proposed research questions were independently scored on a set of criteria: feasibility, impact on health, impact on the economy, capacity building, and equity. Following the prioritization of Research Questions (RQs), they were all classified using the 5 Pillar frameworks. Results In total, 145 Research Questions were systematically scored by experts against five criteria. Iran's top 20 road traffic safety priorities were established. The RQs related to “road safety management” and “road and infrastructure” achieved a high frequency. Conclusions The top 20 research questions in the area of RTCs in Iran were determined by experts. The majority of these RQs were related to “road safety management”. The results of this study may contribute to the optimal use of resources in achieving long-term goals in the prevention and control of road traffic crashes and its related injuries. Considering these RQs as research investment options will improve the current status of Road Traffic Injuries (RTIs) at a national level and further advance toward compliance with international goals. If these research priorities are addressed, and their findings are implemented, we can anticipate a significant reduction in the number of crashes, injuries, and deaths.