Human Response to Longitudinal Perturbations of Standing Passengers on Public Transport During Regular Operation.

Simon Krašna,Astrid Linder,Robert Thomson,Jia-Cheng Xu,Arne Keller,Corina Klug,Ary P Silvano

doi:10.3389/fbioe.2021.680883

Abstract

This study investigates the response of standing passengers on public transport who experience balance perturbations during non-collision incidents. The objective of the study was to analyse the effects of the perturbation characteristics on the initial responses of the passengers and their ability to maintain their balance. Sled tests were conducted on healthy volunteers aged 33.8 ± 9.2 years (13 males, 11 females) standing on a moving platform, facilitating measurements of the initial muscle activity and stepping response of the volunteers. The volunteers were exposed to five different perturbation profiles representing typical braking and accelerating manoeuvres of a public transport bus in the forward and backward direction. The sequence of muscle activations in lower-extremity muscles was consistent for the perturbation pulses applied. For the three acceleration pulses combining two magnitudes for acceleration (1.5 and 3.0 m/s2) and jerk (5.6 and 11.3 m/s3), the shortest muscle onset and stepping times for the passengers to recover their balance were observed with the higher jerk value, while the profile with the higher acceleration magnitude and longer duration induced more recovery steps and a higher rate of safety-harness deployment. The tendency for a shorter response time was observed for the female volunteers. For the two braking pulses (1.0 and 2.5 m/s2), only the lower magnitude pulse allowed balance recovery without compensatory stepping. The results obtained provide a reference dataset for human body modelling, the development of virtual test protocols, and operational limits for improving the safety of public transportation vehicles and users.

Highlights

The safety of passengers on public transport is a prerequisite for a sustainable transport system, as even minor incidents and frequent discomfort can discourage vulnerable people from using public transport
We compared the characteristics of the initial muscle and kinematic responses of healthy volunteers subjected to typical balance perturbations that can be experienced by standing passengers on public transport
This study investigated the response of standing passengers on public transport to balance perturbations, establishing a reference set of experimental data for estimating safe operating envelopes

Summary

Introduction

The safety of passengers on public transport is a prerequisite for a sustainable transport system, as even minor incidents and frequent discomfort can discourage vulnerable people from using public transport. A recent study (Silvano and Ohlin, 2019) found that the circumstances for Standing Passenger Response to Longitudinal Perturbation which passenger falls occur, and the groups typically affected, are different during acceleration and braking. During acceleration and turning from the bus stop, passengers fall after boarding, while attempting to become seated This affects those aged 65+ and female users in particular, who are overrepresented among public transport users in these type of non-collision incidents on buses (Kirk et al, 2003; Albertsson and Falkmer, 2005; Björnstig et al, 2005; Halpern et al, 2005; Kendrick et al, 2015; Barnes et al, 2016). Some researchers observed no gender-related differences in the response to standing-posture perturbations (De Graaf and Van Weperen, 1997)

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