Calculating exactly how many roads are “necessary” to create a thriving society is very difficult. For example, we need some amount of farms in rural areas, so

Calculating exactly how many roads are “necessary” to create a thriving society is very difficult. For example, we need some amount of farms in rural areas, so we need at a minimum roads to those cars. But we probably also don’t want to force farmers to live completely isolated, so farmers need some amount of rural community. Stores, schools etc… then we need fire, police, water, power. And all of those things require roads for access and maintenance. Then add in the fact that none of this is centrally planned, and that there’s a definite need for redundancy.