Are Belgians really doing 28 MPH on a regular basis?
EU vehicle category L1e, if you want to look up the exact word in your own language.
I don't think there are specific speed limits for bike lanes, or bikes, anywhere in the EU (but of course I could be wrong).
My 18 miles commute is 2 miles of sleepy suburban traffic and 16 miles on the SF Bay Trail (IOW: flat dirt track with no cars allowed.) Even if it were all dirt track, I'd still be wearing my helmet.