I guess if you were technical about the wording, a (max) speed limit is the limit, no exceptions allowed; it doesn’t matter if it’s safer to travel more quickly, it doesn’t matter if it’s more fuel efficient, it doesn’t matter if getting somewhere more quickly is a life-or-death situation, that limit’s the absolute maximum allowed unless you’re one of The Exempted. The way it’s measured allows a bit of leeway in some states, but the limit’s still the maximum speed according to the law, the leeway’s only there to allow for potential inaccuracies in the measuring process/equipment.
Wheres the “lower limit” doesn’t exist as a limit per se, you‘re just not allowed to operate a vehicle on the road slowly without reasonable cause. Being a cyclist is one of those reasonable causes, if you were transporting someone to hospital where bumps in the road at speed were going to exacerbate their condition that’d be reasonable.
So if we were being cough about the wording, it’s true to say there’s no lower limit, but it’s not true to say you’re immune from Plod Prejudice &/or Random Road Usage Tax when travelling under the max limit.
Not in Straya at least. That minimum limit in certain parts of the US, I assume that’s a safety thing, like in rockfall zones … or is it just about stopping numpties from holding-up traffic?
Not following the same rules as the local roads is rare, few countries do that; unless it’s signposted differently (which the London escalators are), in the UK slower pedestrian-traffic sticks to the left & hence on escalators/travelators you stand to the left.
An image search gives a result which claims to be at Heathrow, you can see 3 blue circles on the RHS down near the footway at the start of the travelator and one of those blue circles says it’s stand to the left. But I can’t really tell whether it’s actually a pic from Heathrow.