Fun fact about Roman roads: The Romans would build roads as straight as physically possible. Unlike the modern day, where we will wrap a road around the landscape to keep it relatively level, the Romans would direct their roads straight up and down hills to keep them as short as possible.
Also, on the subject of maps of Rome that look like subway maps, the Peutingeriana https://en.wikipedia.org/wiki/Tabula_Peutingeriana is supposedly based on a Roman original and definitely feels like a subway map, prioritizing the connections between cities rather than their correct spatial distribution.
This makes a lot of sense actually, motorized vehicles have a lot more trouble with slopes than people (and pack animals) do.
Also, in Roman times road construction had to be done entirely by hand and out of stone. Modern "pouring" of roads with asphalt or concrete was not yet a thing back then, so it makes sense to try and limit the hard work of construction as much as possible.
Now that we have electric vehicles with torque from 0 rpm, and regenerative braking, we can go back to straight roads ...
(Just the other day I was observing that zigzag roads up/down mountains were probably a consequence of engines unable to apply power at very low speeds and friction brakes.)
Ruler-straight roads make a lot of sense when you're trying to rule a vast empire where the speed of communication is the travel time of your messengers. The roads are basically both transportation and telecom infrastructure.
Also, on the subject of maps of Rome that look like subway maps, the Peutingeriana https://en.wikipedia.org/wiki/Tabula_Peutingeriana is supposedly based on a Roman original and definitely feels like a subway map, prioritizing the connections between cities rather than their correct spatial distribution.