Search

Horizontal curves, as one of the most accident-prone parts of the road, have always attracted special attention. When a vehicle is moving on a road, the driver has to be constantly on the lookout for small deviations from the main route, possibly due to disturbances such as wind, road roughness, and unwanted entrances by the driver. These types of deviations have a corrosive effect on the driver and will eventually lead to the overturning and slipping of vehicles, so they should be minimized. AASHTO standard procedures, as the most valid road design bylaw, do not consider the effect of lateral wind, in which the effect of lateral wind in arcs has been investigated in this research. The work conducted in this research is to increase knowledge about the directional stability of vehicles that are affected by strong winds and to investigate the parameters of the study using accurate models of dynamic simulation of vehicles that are subject to winds. This study aimed to increase the understanding of vehicle sensitivity to wind due to strong lateral winds. For this purpose, the process of passing different types of vehicles through horizontal arcs in different longitudinal slopes with different velocities of the vehicle under lateral wind is simulated and the mechanical properties of vehicles under such conditions are calculated to compare with the results obtained from the passage of vehicles through a smooth horizontal arc (without longitudinal slope) and without lateral wind. Overturning angle, slip angle, lateral acceleration, and lateral coefficient of friction of vehicles in this study were calculated through software outputs, and the effect of lateral wind on the safety of arcs has been investigated. [ABSTRACT FROM AUTHOR]

Speed humps are in widespread use around the world. Despite their effective performance in increasing safety, they cause considerable damage to vehicles and discomfort to drivers and passengers. This paper investigates the dynamic response of vehicles on different types of speed humps using a multibody simulation software package that is popular in the automotive industry. Following this evaluation, two new profiles are recommended to optimize the dynamic performance of speed humps. A series of formulas are also presented to estimate the dynamic performance of passenger cars on flat-topped and parabolic humps based on vehicle speed, hump dimensions, and driving behavior while traversing the hump. The results show that, for flat-topped humps, the ramp length (or entrance slope) has the greatest effect on vehicle performance. It is found that the dynamic performance of the recommended profiles is much better than that of conventional humps. [ABSTRACT FROM AUTHOR]