Integrated bicyclist protection systems:​ potential of head injury reduction combining passive and active protection systems

Fredriksson, Rikard; Ranjbar, Arian; Rosén, Erik

Affiliations

Abstract

In recent years both pedestrian passive and active safety systems, such as pedestrian bonnets/airbags and autonomous braking, have emerged on the market and are estimated to be effective to reduce injury of vulnerable road users in car crashes. A natural next step is to develop similar protection systems for bicyclists. The aim of this study was to investigate the potential bicyclist head injury reduction from passive and active protection systems compared to an integrated system.

The German In-Depth Accident Study (GIDAS) database was queried from 1999 to 2014 for severely (AIS3+) head injured bicyclists when struck by passenger car fronts. This resulted in 34 cases where information was sufficient for both the pre-crash and the in-crash part of the event. The default passive protection system was designed to mitigate head injuries caused by the bonnet area, A-pillars, and the lower windscreen (instrument panel) area (deployable hood and windshield airbag). To estimate the hood and airbag performance risk reduction functions were used based on experimental tests with and without the systems. The active protection system was an autonomous braking system, which was activated one second prior to impact if the bicyclist was visible to a forward-looking sensor. Maximum speed reduction was estimated using road condition information in each case. The integrated system was a direct combination of the passive and active protection systems. Case by case the effect from each of the active, passive and integrated systems was estimated. For the integrated system, the influence of the active system on the passive system performance was explicitly modelled in each case. A sensitivity analysis was performed varying the coverage area of the passive protection system and the activation criteria of the active system.

The integrated system resulted in 29%-62% higher effectiveness than the best single system of active respectively passive protection system in reducing the number of bicyclists sustaining severe (AIS3+) head injuries. These values were statistically tested and found to be significant. The study is based on representative data from Germany, but may not be representative to countries with a different car fleet or infrastructure. This study indicates that integrated systems of passive and active vulnerable road user countermeasures offer a significantly increased potential for head injury reduction compared to either of the two systems alone.

Links

URL: http://www-esv.nhtsa.dot.gov/Proceedings/24/files/24ESV-000051.PDF

Cited Works (11)

Year	Entry
2014	Fredriksson R, Rosén E. Head injury reduction potential of integrated pedestrian protection systems based on accident and experimental data: benefit of combining passive and active systems. In: Proceedings of the 2014 International IRCOBI Conference on the Biomechanics of Injury. September 10-12, 2014; Berlin, Germany.603-613.
2009	Kerrigan J, Arregui C, Crandall J. Pedestrian head impact dynamics: comparison of dummy and PMHS in small sedan and large SUV impacts. In: Proceedings of the 21st International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 15-18, 2009; Stuttgart, Germany.
2001	Fredriksson R, Håland Y, Yang J. Evaluation of a new pedestrian head injury protection system with a sensor in the bumper and lifting of the bonnet’s rear part. In: Proceedings of the 17th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 4-7, 2001; Amsterdam, The Netherlands. SAE 2001-06-0089.
2012	Fredriksson R, Rosén E. Priorities for bicyclist protection in car impacts: a real life study of severe injuries and car sources. In: Proceedings of the 2012 International IRCOBI Conference on the Biomechanics of Injury. September 12-14, 2012; Dublin, Ireland.779-786.
2008	Kerrigan JR, Crandall JR, Deng B. A comparative analysis of the pedestrian injury risk predicted by mechanical impactors and post mortem human surrogates. Stapp Car Crash J. 2008;52:527-567. SAE 2008-22-0020.
2009	Naci H, Chisholm D, Baker TD. Distribution of road traffic deaths by road user group: a global comparison. Inj Prev. February 2009;15(1):55-59.
2012	van Schijndel M, de Hair S, Rodarius C, Fredriksson R. Cyclist kinematics in car impacts reconstructed in simulations and full scale testing with Polar dummy. In: Proceedings of the 2012 International IRCOBI Conference on the Biomechanics of Injury. September 12-14, 2012; Dublin, Ireland.800-812.
2010	Rosén E, Källhammer J-E, Eriksson D, Nentwich M, Fredriksson R, Smith K. Pedestrian injury mitigation by autonomous braking. Accid Anal Prev. November 2010;42(6):1949-1957.
2009	Rosén E, Sander U. Pedestrian fatality risk as a function of car impact speed. Accid Anal Prev. May 2009;41(3):536-542.
2012	Fredriksson R, Bylund P-O, Öman M. Fatal vehicle-to-bicyclist crashes in Sweden: an in-depth study of injuries and vehicle sources. In: 56th Annual Proceedings, Association for the Advancement of Automotive Medicine (AAAM). October 14-17, 2012; Seattle, WA.25-30.
2007	Masson C, Serre T, Cesari D. Pedestrian-vehicle accident: analysis of 4 full scale tests with PMHS. In: Proceedings of the 20th International Technical Conference on the Enhanced Safety of Vehicles (ESV). June 18-21, 2007; Lyon, France.

Cited By (2)

Year	Entry
2019	Zhao Y, Ito D, Mizuno K, Kong C. AEB effective evaluations by accident reconstructions using videos of drive recorders in perpendicular and turning car-to-cyclist collisions. In: Proceedings of the 2019 International IRCOBI Conference on the Biomechanics of Injury. September 11-13, 2019; Florence, Italy.243-255.
2020	Pipkorn B, Alvarez V, Fahlstedt M, Lundin L. Head injury risks and countermeasures for a bicyclist impacted by a passenger vehicle. In: Proceedings of the 2020 International IRCOBI Conference on the Biomechanics of Injury. 2020; Munich, Germany.289-306.