Objective  To examine the prevalence and influencing factors of helmet wearing among E-bike drivers and passengers in Shanghai for providing evidence to road traffic injury prevention.

  Methods  From October 2015 to April 2019, totally eight waves of observational survey were carried out at eight traffic intersections selected with stratified random sampling in Shanghai city. The number of E-bike drivers and passengers passing through the traffic intersections were counted and the frequency of helmet wearing among the passers was calculated.

  Results  The ratio of helmet wearing was 14.12% among the 84 232 E-bike drivers and only 1.99% among the 10 540 E-bike passengers observed during the surveys. The results of the bivariate probit model analysis show that the helmet wearing is 0.14 probability unit lower in the female drivers than that in the male drivers; the helmet wearing in the E-bike drivers carrying adult passengers is 0.28 probability unit higher than that in the drivers carrying minor passengers; and the E-bike drivers′ helmet wearing in winter season is 0.52 probability unit higher than in summer season (all P < 0.01). The helmet wearing in the female E-bike passengers is 0.14 probability unit lower than in the male passengers and the E-bike passengers′ helmet wearing in winter season is 0.37 probability unit higher than in summer season (both P < 0.001). Marginal effect analyses reveal that the probability of E-bike drivers′ helmet wearing in winter season is 14% higher than that in summer season and 13% higher when carrying adult passengers than that when carrying minor passengers (both P < 0.001); when carrying passengers not wearing helmet, the probability of helmet wearing in the female E-bike drivers is 2% lower than that in the male drivers; all the E-bike drivers′ helmet wearing when carrying adult passengers is 4% higher than that when carrying minor passengers and is 6% higher in winter season than in summer season (all P < 0.05). The probability of helmet wearing in E-bike passengers carried by drivers not wearing helmet in winter season is 1% higher than that in summer season (Z = 3.24, P < 0.001).

  Conclusion  The prevalence rate of helmet wearing among E-bike drivers and passengers in Shanghai is generally low and presents a seasonal fluctuation. The helmet wearing of E-bike drivers and passengers is lower in females that than that in the males and helmet wearing behavior of the drivers and passengers interact each other.