TITLE:
Characterisation of Real-World Bus Acceleration and Deceleration Signals
AUTHORS:
Marietta Kirchner, Patric Schubert, Christian T. Haas
KEYWORDS:
Bus Acceleration Signal; Complexity Index; Similarity; Legendre Polynomials; Postural Control; Perturbation; Ecological Validity
JOURNAL NAME:
Journal of Signal and Information Processing,
Vol.5 No.1,
February
10,
2014
ABSTRACT: Public transportation by
bus is an essential part of mobility. Braking and starting, e.g., approaching a
bus stop, are documented as the main reason for non-collision incidents. These
situations are evoked by the acceleration forces leading to perturbations of
the passenger’s base of support. In laboratory studies perturbations are applied
to getting insight into
the postural control system and neuromuscular responses. However, bus perturbations
diverge from laboratory ones with respect to duration, maximum and shape, and
it was shown recently that these characteristics influence the postural
response. Thus, results from posturographic studies cannot be generalised and
transferred to bus perturbations. In this study, acceleration (ACC) and
deceleration (DEC) signals of real traffic situations were examined. A
mathematical approach is proposed in order to identify characteristics of these
signals and to quantify their similarity and complexity. Typical
characteristics (duration, maximum, and shape) of real-world driving manoeuvres
concerning start and stop situations could be identified. A mean duration of
13.6 s for ACC and 9.8 s for DEC signals was found which is
clearly longer than laboratory perturbations. ACC and DEC signals are more
complex than the used signals for platform displacements in the laboratory. The
proposed method enables the reconstruction of bus ACC and DEC signals. The data can be used as input for studies
on postural control with high ecological validity.