I estimate I was heading uphill at about 15mph and three ebikes overtook me at my estimate of nearly 30mph based on local knowledge of the road and the speed the cars were doing.
Any e bike going uphill at over 15mph surely has an illegal, over 250 watt, motor?
On the road yes, not off road in the woods. I’ve seen e mtb on forest tracks in Dolomites and definitely not e pedalec compliant.
Off road legality gets complicated. My understanding is that under UK law, anything capable of going faster than 15mph is a mechanically propelled vehicle and so can't be used on Bridleways, period. It
could be legal on BOATs and RUPPs, but only if registered and insured
as a mechanically propelled vehicle (ie moped or motorcycle, depending on top speed). Use away from recognised rights of way would not be illegal, but is unlawful unless you have the landowner's permission. [It could be illegal is you cause damage, but on the basis of criminal damage law, not vehicle use]. Then there are police powers under anti-social vehicle use powers, but I don't know much (anything!) about those, so won't speculate.
So a 'not road-legal' Ebike is also not legal on other RoWs because the laws governing its classification for road use also apply on other rights of way. Just like an unregistered/untaxed/uninsured MX bike. Ride one on a byway and you could theoretically get a motoring conviction. But the chances of enforcement are, of course, negligible. I suspect that the only way users will get the message is if a few people get stung for high-value third party liability claims, leading to constabulary attention for driving without licence and/or insurance.
In theory, de-regulated Ebikes could be permissible at trail centres if the operator is happy. I'm not aware of any that do encourage it. And trail centres tend to be designed around slow-up, fast-down principles so >15mph capability seems pointless to me. That's not to say that an 'Ebike ascent route' couldn't be added, of course.
What's legal or not in the Dolomites is an open question...