Introduction Motorcyclists account for two-thirds of traffic across Southeast Asia, and in Indonesia, comprise 36% of all road traffic deaths. Although helmets significantly reduce the risk of serious injuries and death, their use remains low. With increasing penetration of mobile phones, the risk of distracted driving may compound the risk of limited helmet use.

Methods Data on 1 20 579 motorcycle drivers and 43 132 passengers were collected through observation at ten locations in Bandung, Indonesia in March, April and August 2017. Multivariable logistic regression was used to evaluate associations between handheld phone use and driver demographics, time, place, and helmet use.

Results 76.08% of motorcycle drivers and 48.12% of passengers were observed to wear helmets correctly. Female occupants had lower prevalence of helmet use (56.10%) compared to males (74.10%) (OR: 2.24, p<0.001). Passengers over 18 had almost 6 times the odds of wearing a helmet correctly compared to passengers under 18 (OR: 5.77, p<0.001). 3.66% of motorcycle drivers were observed using a hand-held phone. Controlling for age, sex, time of day, weekday, and location, drivers wearing helmets correctly were more likely to use a handheld phone, compared to drivers not wearing or incorrectly wearing helmets (OR: 1.36, p<0.001).

Discussion The effect of being a passenger or driver on helmet use is modified by age; while adults in all positions were more likely to wear a helmet, the age effect was larger among passengers than drivers. Interestingly, drivers wearing helmets had higher odds of engaging in a different risk factor, the use of a handheld phone. This may indicate risk compensation; drivers who believe themselves to be protected in the event of a collision may engage in behavior that can increase the risk of that event. Programs addressing the use of helmets ought to also include distracted driving to address this risk.