Although several previous studies have focused on pedestrian safety, most of the studies have focused on urban roads. This study investigated accident data among 1358 pedestrians from 2012 to 2018 on urban, suburban, and rural roads in 16 cities in the Gilan province of Iran using structural equation modelling (SEM). Factor analysis showed that four exogenous latent variables had a significant relationship with fatal accidents among pedestrians. Factors related to roads (coefficient: 0.968), vehicles (coefficient: 0.632), humans (coefficient: 0.306), and the environment (coefficient: 0.194) were respectively the most important for pedestrian safety status. The main findings also proclaim that the poor quality of cars manufactured in Iran in addition to the poor design of intersections and major roads (urban) and ring roads (suburban) may be important reasons of the increased fatal accidents in the studied areas. A potential cause for these accidents may be rooted in less attention towards giving behavioural instructions to road users, and underdeveloped driver education procedures. Finally, the data-model fit of the SEM was validated using different indicators, and suggestions to improve safety were pointed out.

The simultaneous reduction of the project cost and time has paramount importance in today's competitive world; however, it is necessary to balance the project time and cost because of the reduction asymmetry of the two factors in a project. How to balance the cost and time parameters in managing construction projects is also critical and there have always been some attempts made to provide different approaches to control it. Given the immense importance of considering resource constraints for project scheduling problems, and the proximity of the study conditions to the real world, resource constraints were also included. In a project, project managers need to be aware of resource constraints. As resource constraint scheduling problem is considered NP-hard, the metaheuristic models were developed in this paper in order to obtain results contributing to project managers’ decision-making. For this purpose, a non-dominated sorting genetic algorithm method was developed to optimize a time-cost trade-off problem. Furthermore, to solve a multi-project scheduling problem, the critical chain method was used. In order to evaluate the performance of the model, the developed model was first studied in a small scale and then simultaneous projects with 7, 8 and 10 tasks were planned. Because resource availability is essential in such problems, after solving the proposed model, a sensitivity analysis was performed for daily resources and the results were discussed. Results shows the ability of the proposed model and methodology to optimize the time-cost tradeoff considering resource constraints in sample problems. Solutions obtained showed that in some cases of scheduling without this algorithm, resource consumption exceeded above resource availability. After solving the model by proposed algorithm, resource allocation is implemented considering resource constraint. This model determined these resources as crucial and helped managers to control them.