Confusion

So I drove in my hometown most of the time in Modesto, but I notice whenever I leave my town the map changes and shows icons for high traffic areas (I assume that’s what the icons are) but I never see these in my own town, also when I drive in my town the fares are only 30 - 50 cents a mile and when I go to these other cities it’s anywhere from $2-$4 a mile, my city is not a small city so I’m not sure why it’s so bad here