Answer:
It decreased the cost of shipping while reducing the time to travel to the West
Step-by-step explanation:
The important effects that came from the improved transportation system of roads and canals in America are that "it decreased the cost of shipping while reducing the time to travel to the West."
This is evident in the fact that improved transportation systems of roads and canals led to easy access to the western part of the USA where new settlements and farms were located. This transportation system linked both the East Coast and the West coast easily, and thereby reduce the cost of transportation and time travel.
For example Erie Canal, Cumberland Road, etc.