And that's why it's disingenuous to frame cycling safety as a binary that's contingent on whether or not a particular cyclist is wearing a helmet. The risk equation for you is vastly different from someone who hops on their cruiser bike to go 10 blocks on a protected bike trail to the grocery store.

Once you factor in all the variables, the helmet is only a small part of the equation, and probably not going to do you much good should you find yourself under the wheels of a semi-truck. Yet having that piece of styrofoam strapped to your head has given you the (possibly misplaced) confidence to go fast with semi-trucks.

That's classified as an electric motorbike in the EU, if it's a legal, registered vehicle. You need the appropriate driving license and insurance to drive one.

Alternatively, if it's a modified bicycle, it's simply illegal on public roads.

The helmet isn't going to protect you from semis, unfortunately. Here in NYC most cyclist deaths are caused by being run over by larger vehicles, which can easily be fatal even at slow speeds regardless of whether you're wearing a helmet or not. No helmet is going to support the weight of a truck.

Now I do wear a bike helmet when biking for other reasons, but I give trucks wide leeway.

You're welcome to wear whatever you want while riding your illegal whatever-you-call-it. Don't scold the rest of us.