Influência da aderência pneu-pavimento nos conflitos veiculares microssimulados

Abstract

The relationship between Road Safety (RS) and road skid resistance is furtherly complex, since one cannot certainly comprehend the combined effects of friction and driving behavior, especially during rainy days. Therefore, this research aimed to assess how would it be possible to consider surface condition on Road Safety Performance (RSP). It was proposed to assess different scenarios in a typically Fortaleza, Brazil urban environment, through surrogate measures of safety. This approach was chosen based on the possibility of using a microscopic traffic simulator, with which is allowed to obtain a greater amount of detailed data with records of the dynamics of simulated vehicles. Literature review converged to Free-Flow Speed (FFS) and Saturation Flow (SF) as key parameters susceptible to adverse weather. To evaluate surface condition, it was selected a segment of a typical Fortaleza, Brazil arterial road to perform the British pendulum test (AST E303-93, 2013) and the sand patch test (ASTM E965, 2015). International Friction Index (IFI) reported both micro- and macrotexture in friction coefficient, which was used to determine Maximum Available Deceleration Rate (MADR). MADR was then compared to Deceleration Rate to Avoid the Crash (DRAC) to evaluate the severity of vehicular interactions. Thus, this research highlighted the existence of driving behavior adjustment due to precipitations, keeping a larger safety distance among each other, which led to an 8% SF reduction. This adjustment was represented on VISSIM, by a car-following W74 model calibration. Important result of this research pointed to the occurrence of more severe conflicts in situations of major adversity (4.3 times greater), emphasizing the importance of driving behavior adjustment due to external stimulus.