These lines are roads, I don't think it means much, just that there's bigger road density or something. It's probably due to the amount of cities and their population, more of both means more roads (and other ways of transportation too)

Edit: ok, this is probably just google maps so those are roads and maybe passenger train lines (idk if they include those, never saw them, but there are none where I live, so idk)

also has actual high speed rail which nobody in US has

Is Coruscant from star wars the end goal?