Can You Feel The Difference? The Just Noticeable Difference of Longitudinal Acceleration

In developing the next generation of engines and powertrains in the automotive industry, a deep knowledge of acceleration and its perception by the customer is essential. Because the vehicle’s longitudinal acceleration is one of the most dominant factors in perceived driving experience, the desired increase or accepted decrease of this factor should be carefully controlled. The main objective of the present study is to identify the point at which the difference in longitudinal acceleration becomes just noticeable. In particular, this means locating the minimum point at which a vehicle’s acceleration can differ from another and still be noticed by the subject. For this purpose, an experimental vehicle was equipped with an application control device, which allowed the vehicle’s acceleration performance to change within a few seconds. That on the other hand enabled an experiment to be conducted with 16 subjects and using adapted methods from the field of psychophysical research. The obtained threshold of about 0.1m/s² (level of maximum acceleration) and about 1m/s³ (acceleration gradient, 95% confidence interval) demonstrated a way that this research problem can be taken from the laboratory and applied under real life conditions to obtain applicationoriented results.