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

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.

Accelerations of public transport vehicles: A method to derive representative generic pulses for passenger safety testing

“…In non-collision incidents involving public transportation vehicles, standing passengers are often subjected to balance perturbations due to the acceleration and deceleration of the vehicle. The balance recovery and mitigation of possible injury depend on the perturbation pulse properties, as presented in biomechanical studies (Karekla and Tyler, 2018;Krašna et al, 2021). However, typical bus acceleration and deceleration pulses are difficult to replicate in a laboratory setup.…”

“…However, the peak values appear at roughly similar times (the peak in the absolute value of the acceleration appears after the first rise, while positive and negative peak jerks appear in the first rise or the last drop). Given that peak jerks and peak accelerations together with the points in time when they appear are the relevant quantities for the severity of an acceleration perturbation to standing passengers (Krašna et al, 2021), the severity of the maximum similarity pulse seems not to be due to the random peaks and oscillations, but rather due to features which are also present in the mean pulses. Therefore, the mean pulses, scaled in time and magnitude to the desired severity, likely provide sufficiently realistic and convenient input to numerical or physical tests, given the advantages discussed above.…”

Influence of Public Bus Driver’s Driving Behaviors on Passenger Fall Incidents: An Analysis Using Digital Tachograph Data

“…Te driving style can afect a standing passenger's risk of losing balance. Several studies also analyzed fall incidents on buses [31,32].…”

Experimental testing of longitudinal acceleration in urban buses

“…Longitudinal acceleration exceeding 2.0 m/s 2 is deemed by passengers as very uncomfortable [13]. Papers [14,15] present longitudinal acceleration recorded at various speeds and in various traffic conditions, deemed as uncomfortable by sitting, standing and moving passengers. As demonstrated in papers [15][16][17], longitudinal acceleration exceeding 2.0 m/s 2 is dangerous for standing and moving passengers.…”

“…Papers [14,15] present longitudinal acceleration recorded at various speeds and in various traffic conditions, deemed as uncomfortable by sitting, standing and moving passengers. As demonstrated in papers [15][16][17], longitudinal acceleration exceeding 2.0 m/s 2 is dangerous for standing and moving passengers. Balance is at risk in possible-accident situations and the passengers may not be able to cling to the handrail.…”