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

Artikel i vetenskaplig tidskrift, 2019

The number of e-bike users has significantly increased over the past few years and with it the associated safety concerns. In fact, e-bikes are faster than traditional ones and more prone to be in conflict with road users, so that e-bike riders may need to perform avoidance manoeuvres more frequently than traditional riders. Braking is the most common avoidance manoeuvre, but also a complex and critical task in emergency situations, since cyclists must reduce speed in a short time while maintaining their balance.

The aim of this study is to understand the braking strategies of e-bikers in real-world traffic environment and to assess the road safety implications. This paper used data from the E-bikeSAFE naturalistic study to investigate 1) how cyclists use front and rear brakes during routine cycling and 2) whether this behaviour changes during unexpected conflicts with other road users.

In most of events requiring a braking manoeuvre, cyclists used one brake at a time during routine cycling, favouring one of the two brakes according to a personal pre-established pattern. However, different cyclists exhibited different braking strategies and the favoured brake varied among cyclists (66% favoured the rear brake and 16% the front brake). Only a few cyclists (16%) did not show a clear preference,  using rear brake, front brake, or combined braking (both brakes at the same time) non-systematically, suggesting that the selection of what brake to use was based on the characteristics of the specific scenario that the cyclist experienced rather than personal preference.

In a subset of unexpected conflicts, 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. The kinematic analysis revealed that, when larger decelerations were required, cyclists more frequently used combined braking instead of single braking.

The results provide new insights into the behaviour of e-bikers and support the development of safety measures including guidelines and best practices for the optimal use of front and rear brakes. The results may also inform the design of braking systems that may sreduce the complexity of the braking operation.