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This paper focused on the vehicle path planning in the highways and complex urban environments. At first, obstacles and road lines have been detected by sensors of the intelligent vehicle, thereupon the vehicle will be find the safe areas using the time distance method developed in this paper. Then, an appropriate path close to the intelligent decisions about human being would be chosen through the developed algorithm. There is the possibility of collision to surrounding vehicles in the areas where changing the lane is needed. Therefore, to prevent collision, a five orders polynomial curve is offered for each lane change maneuver. The reached maneuver is optimized based on the vehicle dynamic and allowed lateral acceleration. Finally, a suitable path to pass quite safely and without any collision through the obstacles is suggested. At the end, two main and different simulation scenarios included the lack of collision is verified by MATLAB software and the obtained path is controlled by the sliding mode controller. These simulations indicated effectiveness of this method. The lateral acceleration is obtained in allowed range for comfort of occupants in these scenarios.

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With the increasing number of road accidents and driver assistance systems development, the automated vehicles importance has increased more than ever. As the issue of automated vehicles comes up, attending to their safety, and the impact of the other vehicles in traffic flow on their performance dramatically increased. One of the most important problems for automated vehicles is designing and controlling the trajectory regarding the surrounding vehicles in transient dynamic traffic conditions during complicated maneuvers. Although various studies have been performed in the field of lane change in dynamic traffic conditions and even in critical high speed, considering the transient dynamic conditions has been limited to the beginning of the maneuver and no solution has been provided for the surrounding vehicles’ immediate changes during the maneuver. The algorithm presented in this paper is able to design new safe optimized trajectories according to the sudden decisions of the surrounding vehicles during the lane change maneuver, also ensures collision avoidance in the whole maneuver via vehicle’s simultaneous longitudinal and lateral control. After evaluating the decision-making unit’s performance by real driving tests, the presented algorithm is simulated with different scenarios in complicated transient dynamic traffic conditions by using MATLAB software and its desired performance has been proven in the dynamic environment of IPG CarMaker, in the presence of surrounding vehicles.