Funding for this research was provided by:
H2020 Marie Skłodowska-Curie Actions (642662)
Received: 12 November 2018
Accepted: 14 May 2019
First Online: 24 May 2019
Ethics approval and consent to participate
: Those participating in the helmet return schemes gave informed consent for their data to be used in this and subsequent studies. There was no further involvement from any rider.
: No personal data was used in this manuscript.
: Thomas Connor, J. Michio Clark, Matt Stewart, Adrian McGoldrick, Jayaratnam Jayamohan, Claire Williams, Barry Seemungal, Rebecca Smith, Roy Burek and Michael Gilchrist have no competing interests to declare.
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