How to make a street on a procedural terrain?

Hi, i am new to unity and I am not so confirmed with the usable game objects. What is the best way to map a street on terrain with different heights. Is it possible to change the texture on the certain points? Should I use an other Gameobject for the streets? If there is a better solution in unity please help me?

P.S.: If you know a good algorithm for a street in a city please let me know about it ;D

Thank you