People always overestimate their walking pace whether in the city or on a hiking trail. People also overestimate how far they can or thought they walked in a given day.

The SO and went out for a walk/run at the local park late this afternoon. She ran while I walked so I could get some updated elapsed walking pace data just for this thread.

The park trail is 1 km per lap and is a mix of gravel and loose cedar wood chips. I did 5 laps (3.1 miles) in 41.18 minutes which was a relatively easy pace for me considering the uneven, wet and spongy ground. From previous time vs laps over 10 km in this same park, it was a consistent and relative to shorter distance elapsed time for me today. I also know from experience that I can maintain a similar pace on concrete over the same 10 k distance while carrying a 10-12 lb pack as even though concrete is harder on the feet and legs, there is not as much give and softness as compared to non-concrete park trail so I find that my pace is more consistent.

Keeping the above in mind. In a true evac on foot and in an urban environment while carrying a heavier backpack, there is no way I could maintain the same pace for hours and my legs and feet are very well conditioned. I would think that a relatively slow 3 mile per hour pace on decent urban ground and proper footwear over about 8-10 hours would be at the extreme max of my limit per day.