Electric cycles reaching 45km/h are regulated in most of EU, no? On the most powerful ones it takes not too much effort to push to 50 (from experience). That being said, where I commute I practically never encounter anyone doing that (they just do the maximum they can do with assistence, like 42-45 depending on brand and model, or less to save battery/effort) except downhill, where you can reach 50 with a normal cycle as well.

Eu regulates this by classification. A two-wheel vehicle with an electric motor that can assist up to 25 km/h is classified as an electric bike. If the two-wheel vehicle can reach up to 45 km/h, or if it don't require the rider to peddle, then its an electric moped. If it exceeds 45 km/h then its an electric motorcycle.

The classification in turn determines which laws the seller and driver is under. A bicycle doesn't require a driving license or license plate. Mopeds and motorcycles require a license plate (registered) and have corresponding driving licenses. There might also be different taxes involved.

There is a similar classification with four wheel vehicles. There is electric four wheel mopeds, tractors and cars, each defined by the maximum speed. You can even convert a car into a moped or tractor by changing the gear box to limit how fast they can go.

It's easy to remove the safety mechanism. Still, I don't see people going 40+ where I live although maybe that happens in other countries. My experience is that in a city at 30km/h you are passing everyone and with significant speed difference as well.

You download a chinese firmware and flash it of course…

Then your problem isn’t with cyclists, your problem is with jackasses running illegally tuned motorcycles (because that’s what a two-wheeled vehicle that can accelerate beyond 45 km/h is) on bike lanes.