Experimental Study On Effects Of The Car Body Sound Isolation On The Acoustic Situation Awareness Of The External Environment

With the rapid development of the auto industry, more and more vehicles are put on the road every year, which also unfortunately leads to the increase of traffic accidents. To ensure safety, technologies such as seat belts, Anti-lock braking system (ABS) etc., once optional, are now standard equipment for almost all vehicles. On the other hand, as the Intelligent Transportation Systems (ITS) attracts more and more attention, the Advanced Driver Assistance System (ADAS) is also developing fast. Generally the ADAS is an technology helping the driver obtain a better environment awareness of the outside traffic environment surrounding the vehicle. Traditional studies of the ADAS technology focus on the visual signal. But the traditional vision based ADAS technologies generally has higher requirements on equipment, and has limitations that the vision will have, such as block of view, etc.Comparing to the visual signal, the sound signal has a wide detection range and will not be affected by the weather or electromagnetic wave and has no directivity. Sound can be heard in all directions, regardless within or beyond the view of sight. However, the acoustic signal based ADAS is rarely studied so far. The purpose of this study is to investigate the effects of the car body sound isolation capability on the perception of the external traffic sound by the driver, thus to demonstrate the necessity and feasibility of the acoustic based ADAS.First of all, we conduct the sound isolation measuring experiment, get the transmission loss data (TL) in360degree and show them in three-dimension graph and the total TL line in each degree. Then we do several localization experiments with20volunteers with a normal hearing ability in the laboratory. The localization results in Nocar situation and the localization results when the volunteer are put into the car are showed in bubble diagram, we can get the conclusion that the laboratory is suitable for the localization experiment and clearly find the difference in two localization situations. Comparing the bubble diagram to the TL line, the responding conclusions are made. After the signal acquisition of background noise in a car while driving, we simulate the real driving environment and conduct the subjective localization experiment. In the last, we calculate the localization errors and show them in diagram, and do a further analysis to the localization errors. And then, we do the t- test to the localization error in different situations, explain the effect of the car body TL to the localization error using the significance level result (p).Through the analysis to many times experiment data, we fully prove that the research on the sound signal based DAS in necessary.