E-bikers’ braking behavior: Results from a naturalistic cycling study

Abstract

Objective: The number of e-bike users has increased significantly over the past few years and with it the associated safety concerns. Because e-bikes are faster than conventional bicycles and more prone to be in conflict with road users, e-bikers may need to perform avoidance manoeuvres more frequently. Braking is the most common avoidance manoeuvre, but is also a complex and critical task in emergency situations, since cyclists must reduce speed quickly without losing balance. The aim of this study is to understand the braking strategies of e-bikers in real-world traffic environments and to assess their road safety implications. This paper investigates 1) how cyclists on e-bikes use front and rear brakes during routine cycling, and 2) whether this behaviour changes during unexpected conflicts with other road users. Methods: Naturalistic data were collected from six regular bicycle riders who each rode e-bikes during a period of two weeks, for a total of 32.5 hours of data. Braking events were identified and characterized through a combined analysis of brake pressure at each wheel, velocity, and longitudinal acceleration. Furthermore, the braking patterns obtained during unexpected events were compared with braking patterns during routine cycling. Results: In the majority of braking events during routine cycling, cyclists used only one brake at a time, favouring one of the two brakes according to a personal pre-established pattern. However, the favoured brake varied among cyclists: 66% favoured the rear brake and 16% the front brake. Only 16% of the cyclists showed no clear preference, variously using rear brake, front brake, or combined braking (both brakes at the same time), suggesting that the selection of which brake to use depended on the characteristics of the specific scenario experienced by the cyclist rather than on a personal preference. In unexpected conflicts, generally requiring a larger deceleration, combined braking became more prevalent for most of the cyclists; still, when combined braking was not applied, cyclists continued to use the favoured brake of routine cycling. Kinematic analysis revealed that, when larger decelerations were required, cyclists more frequently used combined braking instead of single braking. Conclusions: The results provide new insights into the behaviour of cyclists on e-bikes and may provide support in the development of safety measures including guidelines and best practices for the optimal brake use. The results may also inform the design of braking systems intended to reduce the complexity of the braking operation.

Braking bad – Ergonomic design and implications for the safe use of shared E-scooters

“…The act of braking on a two-wheeler shifts the dynamic wheel load towards the front wheel, hence the front wheel can exert a higher braking force on the ground than the back wheel before slipping occurs between the wheel and the ground (Wilson, Schmidt, & Papadopoulos, 2020;Wolff, 2017). Hence stronger deceleration can be achieved by using the front wheel brake on bicycles (Beck, 2004;Mordfin, 1975;Wilson et al, 2020) although the amount of deceleration further depends on the applied force on the brake lever and braking both wheels is advantageous to single wheel braking (Huertas-Leyva, Dozza, & Baldanzini, 2019). Countries have differing regulations on hand-leverto-wheel coupling for bicycles, with Germany not regulating which lever actuates which brake.…”

Exploring Factors Impacting on the Lane Choice of Riders of Non-Motorized Vehicles at Exit Legs of Signalized At-Grade Intersections

“…Huertas-Leyva et al [ 16 ] collected naturalistic data from six regular bicycle riders who each rode e-bikes during a period of two weeks, for a total of 32.5 h of data, and investigated how cyclists on e-bikes used front and rear brakes during routine cycling. They found out that in the majority of braking events during routine cycling, cyclists used only one brake at a time, favoring one of the two brakes according to a personal pre-established pattern.…”

Exploring Performances of Electric Micro-Mobility Vehicles and Behavioural Patterns of Riders for In-Depth Accident Analysis

“…Testing activities are highlighted and commented on, allowing one to obtain behavioural data on e-bike cyclists in certain road sections, as well as results useful in the analysis of accidents with the involvement of both e-bikes and e-scooters. Real road and closed-circuit tests are reported, which refer to a total of six riders, daily users of traditional bikes, equally divided based on their gender and aged between 25 and 55; such a number of subjects is sufficient to extrapolate interesting information in terms of performance and typical behaviours of riders [25]. The subjects were part of the University of Florence, ranging from students and internal personnel.…”

“…While several interesting highlights emerge from the closed-circuit and real road tests, the number of participants considered in the experiments is limited. While it has been observed that a campaign involving six volunteers is sufficient to determine behavioural patterns of a population [25], future studies should increase this number to fully assess the effects on the user's behaviour caused by age category, gender and riding experience. Additionally, experiments were performed on European roads, with specific traffic rules that do not necessarily extend outside of the continent; as a consequence, rider speed and acceleration habits in non-European countries could significantly differ from those previously reported and would be worthy of investigation in future analyses.…”

“…As a first consequence, certain interesting data are sometimes unavailable during the event analysis, e.g., speed or accelerations on a hypothetical trajectory travelled by the vehicle; conversely, when available from the literature, the data must sustain interpretation and contextualization, making them difficult to employ. For instance, Huertas-Leyva et al [25] highlighted the distribution of the braking force on the rear and front wheels activated by six riders of traditional and electric bikes in case of routine cycling or unexpected emergencies; however, no information was available regarding the speed at the beginning of such braking action, nor the associated type of road (e.g., with/without right of way, roundabouts), which are fundamental to hypothesize the accident dynamics and hence reconstruct the pre-impact scenario. Analogously, Otte et al [26] reported the distribution of accidents involving riders of traditional bikes and e-bikes in terms of road typology and speed separately, but not considering both at the same time.…”