Answer:
Main roads on the mountain and coast side were linked by connecting roads.
Step-by-step explanation:
The Inca empire was one of the most developed civilizations in the Americas and it was the one that had the largest territory. Unlike many other civilizations that formed and prospered in large fertile plateaus, fertile river valleys, or lowlands in general, the Incas were unique in this department. Their civilization was formed on the high Andean Mountains which even after the expansion toward the coastline it remained the core of the empire.
One of the main reasons why the empire prospered was an excellent road infrastructure. Despite a big portion of the empire being located on very rugged terrain, the Incas still managed to build a state of the art roads for that period of time. They also built excellent roads along the coastline as well. While the main roads were roughly parallel to each other, with the coastline ones being very low and the mountain ones being very high, the Incas also built connection roads between them on every crucial point.