As a bicyclist who consistently wears a helmet, unfortunately the statistics suggest wearing a helmet isn't always helpful. Observational and experimental studies show drivers pass cyclists wearing a helmet closer than they do bicyclists without a helmet. Even worse, drivers are more likely to hit cyclists wearing a helmet. Bicycle helmets are designed to protect against head injury in low-speed crashes. They don't protect against massive bodily trauma or prevent higher force head injuries. So while helmets can reduce head injuries if a fall happens, cyclists are not inherently safer overall just because they chose to wear a helmet. I choose to wear one, but the evidence suggests my helmet may only be altering the nature of the danger of biking instead of reducing it.