Fatalities per mile is a tricky metric for comparing across modes, though. At least in the US, people getting cars often comes with adopting a car-centric lifestyle: you move to the suburbs, your commute and trips to the grocery store get significantly longer, etc. This is why fatalities per mile are higher on a bike, but fatalities per trip are actually slightly lower than a car: people with cars take longer trips.

Depends if you limit it to moped - moped collision then the numbers are different. But a car - moped collision is arguably a car fatality not a moped fatality.

That said walking is very dangerous per mile, but cars get a lot more miles on them.

I'd be very curious about the stats. Above 35-40 you quickly notice a change in momentum. At least a car might have better brakes and stability.

Where?

If you're in a place where everyone drives a moped or bicycle and cars are rare, then mopeds are a lot safer. Stick the moped in traffic surrounded by clueless SUV drivers and now the moped is a death-trap.

Go to a place where everyone rides a bicycle and there's no cars and I guarantee the fatality-per-mile rate is ridiculously low. See downtown Copenhagen for example.