They increase a population's mobility. For example:
to get crops to market;
to allow people to seek medical attention;
to move goods and services;
to open recreational and employment opportunities;
the Interstate System in the US was also designed to allow stretches where airplanes could land in times of national emergency;
they allow people to easily evacuate in times of hurricane;
there are many, many more reasons roads are important.
roads are present in our world during the prehistoric times onwards
when elephants and other large animals take same path towards a river every day the forest clears up and becomes a road the more frequently its used the more the plants are cleared and makes it better
now the demand for smoother roads came after the invention of wheel
now thats history part now importance
1) transportation
2)communication
3)infrastructure development
4)exchange of goods and services
thats all i can think off hope i helped