Just along from the Oxford cycle path of dubious value was an ambulance and bicycle. What were they doing
Looking after the cyclist who had come off -no car involved, seemingly- and hit the kerb
After which a large amount of blood was deposited over the scene
Head injuries always bleed a lot, so that may not be a sign of a bad injury, just a messy one. But it does show that sometimes helmets do have a role to play.
Perhaps once the risks of going under a lorry or bus have been eliminated, its time to worry about what happens when you fall off .