| 1. |
- Huertas Leyva, Pedro, 1977, et al.
(författare)
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E-bikers’ braking behavior: Results from a naturalistic cycling study
- 2019
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Ingår i: Traffic Injury Prevention. - : Informa UK Limited. - 1538-957X .- 1538-9588. ; 20:sup3, s. 62-67
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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| 2. |
- Huertas Leyva, Pedro, 1977, et al.
(författare)
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Investigating cycling kinematics and braking maneuvers in the real world: e-bikes make cyclists move faster, brake harder and experience new conflicts
- 2018
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Ingår i: Transportation Research Part F: Traffic Psychology and Behaviour. - : Elsevier BV. - 1369-8478. ; 54, s. 211-222
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Tidskriftsartikel (refereegranskat)abstract
- Pedelecs (e-bikes), which facilitate higher speeds with less effort in comparison to traditional bicycles (t-bikes), have grown considerably in popularity in recent years. Despite the large expansion of this new transportation mode, little is known about the behavior of e-cyclists, or whether cycling an e-bike increases crash risk and the likelihood of conflicts with other road users, compared to cycling on t-bikes. In order to support the design of safety measures and to maximize the benefits of e-bike use, it is critical to investigate the real-world behavior of riders as a result of switching from t-bikes to e-bikes. Naturalistic studies provide an unequaled method for investigating rider cycling behavior and bicycle kinematics in the real world in which the cyclist regularly experiences traffic conflicts and may need to perform avoidance maneuvers, such as hard braking, to avoid crashing. In this paper we investigate cycling kinematics and braking events from naturalistic data to determine the extent to which cyclist behavior changes as a result of transferring from t-bikes to e-bikes, and whether such change influences cycling safety. Data from the BikeSAFE and E-bikeSAFE naturalistic studies were used in this investigation to evaluate possible changes in the behavior of six cyclists riding t-bikes in the first study and e-bikes in the second one. Individual cyclists’ kinematics were compared between bicycle types. In addition, a total of 5092 braking events were automatically extracted after identification of dynamic triggers. The 286 harshest braking events (136 cases for t-bike and 150 for e-bike) were then validated and coded via video inspection. Results revealed that each of the cyclists rode faster on the e-bike than on the t-bike, increasing his/her average speed by 2.9-5.0 km/h. Riding an e-bike also increased the probability to unexpectedly have to brake hard (odds ratio = 1.72). In addition, the risk of confronting abrupt braking and sharp deceleration were higher when riding an e-bike than when riding a t-bike. Our findings provide evidence that cyclists’ behavior and the way cyclists interact with other road users change when cyclists switch from t-bikes to e-bikes. Because of the higher velocity, when on e-bikes cyclists appear to have harder time predicting movements within the traffic environment and, as a result, more often need to brake abruptly to avoid collisions, compared with cycling on t-bikes. This study provides new insights into the potential impact on safety that a cycling society moving to e-bikes may have, indicating that e-cycling requires more reactive maneuvers than does cycling traditional bicycles and suggesting that any distractive activity may be more critical when riding e-bikes compared to traditional bikes.
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| 3. |
- Ljung Aust, Mikael, 1973, et al.
(författare)
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Final measures (Deliverable 5.5)
- 2020
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The main objective of WP5 has been to run a set of field trials with naïve users (i.e. not experts involved in the development of the measures) for all nudging and coaching measures developed in WP2-4. Then, given the outcome of the field trials, the task has been to analyse which impacts these measures may have on road safety along with the cost of implementing them in vehicle fleets and/or infrastructure. All these activities have taken place in Tasks 5.4 (Data collection) and 5.6 (Data analysis).
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