“Evaluation of motorcycle safety barrier normative”

Evaluation of motorcycle safety barrier normative Abstract Powered Two Wheelers (PTWs) are widely employed for individual mobility because of their high capability of blending in traffic and the enjoyment of riding. Unfortunately, PTW riders are one of the most vulnerable groups of road users. An important part of these accidents and fatalities, involves impact against barriers and road restraint systems, especially in non-urban areas, along with serious limb and organ injury. Therefore, it is clear the benefit drawn from devices able to mitigate the consequences of a biker impact against a road restraint system. Recently, some of these devices have been deployed on the market by several manufacturers. Among European Countries, Spain first recognized the need of specific regulations, to evaluate the effectiveness of these devices and to decide which of them are useful in avoiding damage and suitable for road use. So, in 2005 Spain issued UNE 135900 norm, that deals with this task. and soon, an European norm will be issued by CEN, probably mostly based on the Spanish one. It must be acknowledged that UNE 135900 is the first norm that, after years of guilty indifference, deals with the problem of bikers impacting on road restraint systems and consequent evaluation of devices intended to soften their consequences. Though, following the spread of this norm, there are some aspects that should be more accurately specified in further versions or updates. This paper reports an in deep analysis and critical review of UNE 135900 norm, performed in order to highlight his capability to value the real effectiveness of road restraint systems in case of impacts by vulnerable road users as bikers. Beside a close examination of the norm text, numerical models of the crash test stated by the norm have been assembled and simulated. Model parameters were adjusted to match experimental data, supplied by AISICO (Italian Society for Traffic Safety), to achieve validated and realistic models. On these validated models, various simulations were performed to study the effects of slight speed and approach angle variations on test results. As it is obvious, for real crash tests, a certain tolerance gap must be allowed for impact speed and approach angle. The main purpose of numerical analyses was to evaluate the effects of speed and approach angle on injury indexes and investigate if the prescribed tolerance gaps ensure an homogeneous evaluation of the effectiveness of the devices. Beside the expected increasing severity of the impact according with speed, simulations showed a strong influence of approach angle on injury parameters, that quickly rise as the angle grows. This means that a biker protecting device could be tested with an approach angle lesser than the reference value, leading to lesser injury indexes and obtaining a good evaluation, but deceiving the norm spirit. Possible improvements to the norm, in order to avoid this effect, are been considered.