Apparently bicycle helmets are supposed to be used for multiple crashes. There’s a point at which the helmet is structurally damaged on the inside and should not be used again. Unfortunately most cyclists who’ve reached the “breaking point” so to speak have probably been hit one too many times to realize it. So now there’s a solution involving cheese.
A new type of helmet developed by the German research scientists at the Fraunhofer Institute for Mechanics of Materials IWM in Freiburg is embedded with a special scented oil. Once you smack your head a few times, tiny cracks in the helmet will develop. When one of these cracks becomes deep enough to damage the helmet, it will reach the stinky cheese smelling reservoir and release the formunda. The bigger the crack, the bigger the stink (that’s what she said), so you’ll know right away if your helmet is only slightly damaged or if it’s stinking bad enough to replace. The process is still in development so your nose can rest easy for now, but if you see a downed cyclist and he smells like cheese, you know what to do.