Here is a brilliant study of road safety on motorcycles in Myanmar.

The takeaways:

1) Prevalence decreases for each additional rider.
2) Prevalence in motorcycle-experienced Mandalay is triple that of formerly motorcycle-banning Yangon.
3) Children are largely unprotected.

https://www.dropbox.com/s/m8cvk0m61g38mz6/ICAP%202018%20-%20Naturalistic%20Observation%20of%20Motorcycle%20Helmet%20Use%20-%20Felix%20Siebert.pdf?dl=0

Remember the carnage on Vietnam's roads until motorcycle helmets were mandatory and the regulation was enforced?

Jamie