Wearing a helmet and fastening the strap while riding motorcycles or e-bikes

Cost: A helmet costs between 100 and 300 yuan. It takes just 5 seconds to put on each time.
In plain terms: Wearing a helmet and fastening the strap properly reduces a motorcyclist’s risk of dying in an accident by roughly 40%. The chance of suffering a head injury drops by about 70%. The strap must be tightened; a helmet that simply hangs loosely on the head does not count as being worn.
Benefit: Cochrane pooled data from multiple studies. For motorcyclists wearing helmets, the risk of death fell by 42%. The original odds ratio was 0.58, with a 95% confidence interval ranging from 0.50 to 0.68. Head injuries were reduced by 69% (odds ratio 0.31; 95% CI 0.25–0.38).
Evidence grade: A
Sources:Liu BC 等 (2008). Helmets for preventing injury in motorcycle riders. Cochrane Database of Systematic Reviews. https://doi.org/10.1002/14651858.CD004333.pub3
Notes: The helmet strap must be fastened securely. A helmet left hanging on the handlebars does not count as being worn. The figures above apply specifically to motorcycles. For e-bikes, no direct studies exist, but the mechanics of head injury in a crash remain the same.