According to this [0] thread, typical car travel speeds were between 10 and 20 mph. They even mention specifics like:

> in 1904 in NYC the limit was set to 12 mph inside of the city and 15 mph outside of it.

With that 12 mph figure being a little under the average running speed of the record holder marathon runner (26.2 miles in 2 hours flat, so 13.1 mph).

Now of course, most people are not record holding athletes, so sustaining these speeds on foot is not really happening for most. But you can definitely at least keep up for the duration of a sprint. So no real need for a horse even, your own legs can make do, despite these speeds being supposedly unnatural.

You can also sustain these speeds with a bicycle today, not sure about the bicycles of then.

[0] https://www.reddit.com/r/Writeresearch/comments/hmy0h4/what_...