Some analysis on visibility from driver seat

Many experimental surveys allow to know driver’s behaviour. This latter is conditioned both by the psychophysical state and by the road environment. Several studies have been conducted on the interaction between drivers and the environment, as well as other studies have examined some psychological aspects of the driver behaviour. The road vehicles have been improved over time and the manufacturers have adapted the car structural safety features to the current needs of people's safety. Some accidents are caused by blind spots due to vertical structural elements of the passenger compartment. This work tries to highlight how these elements are an obstacle to the conditions of frontal visibility from the driving seat, and how are an implicit problem for the safety. It was decided to investigate the possibilities of free vision for a sample of about 500 cars produced between the year 2007 and year 2016 and marketed in Italy. The cars analysed were divided into displacement classes and for each class the clear and blind viewing angles from the driving seat were determined: in the direction of travel, to right and to left. The displacement classes of the cars investigated were weighted based on the real presence in the Italian vehicle fleet. Over time there have been a decrease in the free angle on the driver's left and an increase in the free angle to the driver's right due to changes in the pillars and the size of the windscreen. The results were used to check some typical driving situations about at-grade intersections, to verify the actual safety conditions and to show which type of rule is more suitable for the different intersection angle of the roads.