Bicycle helmet wearing is not associated with close motor vehicle passing

a re-analysis of Walker, 2007

Jake Olivier*, Scott R. Walter

*Corresponding author for this work

Research output: Contribution to journalArticle

22 Citations (Scopus)
5 Downloads (Pure)


Objectives: To re-analyse bicycle overtaking data collected by Walker (2007) with a view to assess factors associated with close passing (

Method: A re-analysis of 2,355 motor vehicle passing events recorded by Walker that includes information on cyclist's distance to the kerb, vehicle size and colour, city of observation, time of day, whether the event occurred while in a bikelane and helmet wearing. Each variable was considered for a final, multivariable model using purposeful selection of variables. The analysis was repeated using multiple logistic regression with passing distance dichotomised by the one metre rule. Bootstrap p-values were computed using sample sizes computed from conventional values of power and effect size.

Results: The previously observed significant association between passing distance and helmet wearing was not found when dichotomised by the one metre rule. Other factors were found to be significantly associated with close passing including cyclists' distance to the kerb, vehicle size and city of observation (Salisbury or Bristol, UK). P-values from bootstrap samples indicate the significance of helmet wearing resulted from an overly large sample size.

Conclusions: After re-analysis of Walker's data, helmet wearing is not associated with close motor vehicle passing. The results, however, highlight other more important factors that may inform effective bicycle safety strategies.

Original languageEnglish
Article number75424
Pages (from-to)1-7
Number of pages7
JournalPLoS ONE
Issue number9
Publication statusPublished - 25 Sep 2013
Externally publishedYes

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