An impact above 60kph is beyond the design of even a motorcycle helmet. They are primarily meant to protect the head falling onto the road surface and then sliding, an impact that it similar no matter the speed. Even when standing still, a head freefalling from 2 meters (ie bicyclist/motorcyclist tipping over) strikes the ground at 22.5 kph. That single impact is the US/DOT standard for bicycle helms. They don't accommodate sliding or repeated impacts.