Yes it's nothing to do with cycling, and it's not about driving into the park, it's about it being a heavy-duty through road shortcut between northeast of city and southside and the complete and utter lack of respect for the speed limits.
It should be pointed out to those that advocate the "path" as a reason why there should be 25,000 vehicles a day rumbling through a unique beauty spot (how many other cities have extinct volcanoes slap-bang in the middle of town?) that the path provides no alternative round the south of the park to Duddingston.