The league on Roman roads was set at 3mph for foot and for horseback
The vehicle system gets a bit complicated as it mixes apples with oranges as far as functions go and there were specialized types of transport like pony express type mail systems for the state and its commercial counterpart that were focused on faster travel with extremes of around 500 miles covered in 24 hours occuring when circumstances were properly aligned with available route and support
Generally travel by land was avoided if any comparable water routes were available
Obviously this isn't definitive on the subject and a bit of digging turned up a rather interesting rule of thumb in a u.s. forrest service fire handbook giving 3mph horseback 2mph foot as time standards which I find notable as this is a response situation to address an active forrest fire emphasizing speed with safety meaning asap without exhaustion or damaged/lost equipment upon arrival much like would be preferable in military considerations
Idk if the difference between foot and horseback is reasonably attributed to modern transportation availability superseding walking to the point that the gap can be accounted for by simply the more sedentary lifestyle but nonetheless there it is
Still much like the notion that a horse is some kind of atv vehicle when in fact the horse and human are basically equivalent when considering terrain and its passability from a shod/unshod perspective it seems the idea that horse riding generally providing a significant advantage to overall travel speeds doesn't hold up very well on analysis
My poor conceptions
It's assailing the position with information that causes all the issue not the unfounded grounds on which the stands are made
Stupid questioning Me