Street hierarchy is a way of categorizing different roads. There are usually four different types of roads: highways, freeways, main roads, and side roads.
Highways are the biggest and busiest roads. They usually have multiple lanes, which means they can fit a lot of cars. Highways are usually built far away from where people live, so they usually don't have many businesses, buildings, or homes.
Freeways are big roads like highways, but they don't have any stop signs or traffic lights. Freeways are mostly used for long-distance travel because they don't have many exits.
Main roads are smaller roads that are used to connect highways and freeways to smaller towns and cities. They usually have more businesses and homes than highways and freeways so they have more stop signs and traffic lights.
Side roads are the smallest roads. They are found in neighborhoods and around cities and towns. They don't usually have any stop signs, they just have street signs to help people find their way around.