Difference between country roads and streets
Country roads have a higher speed limit and are cheaper. Then, what are the benefits of streets?
Cities will only place buildings on streets.
Country (fast) roads in a city will be converted to city (slower) roads to allow the growth of the city.
If you want to guide how a city is to grow, build with streets
If you are trying to have a fast road for trucks to come into the city, build with the cheaper country roads