Answer:
it is used as a pathway that vehicles can use to reach their destination efficiently.
Step-by-step explanation:
Land Vehicles can still move without roads, but roads provide an ideal surface and spacing that accommodate a lot of vehicles to move at the same time without being stucked or collided with one another.
Canals have similar function with this, but it is designed specifically to accommodate water vehicles (boats or ships). We rarely see canals in Untied States. But cities like Venice in Italy implemented canals really well.