|Game Trail in Northeast |
Sometimes you'll find trails that are made by pedestrians which cut through fields, or small stands of trees, or cut across a lawn. These trails exist because it is easier--that is, less energy intensive--to get from point A to point B using them, rather than bushwhacking a new trail, or following the orthogonal roads or sidewalks, and making the walk 41% longer. In a pastoral world, these human trails crisscross the landscape, however, in an industrial society, only small segments of these trails connect roads.
In an industrial society, machines overcome the limitations of human power production. The energy that's stored in a cup of gasoline exceeds the amount of energy stored in a cup of food by orders of magnitude, for example 31,500 calories versus 320 calories for a cup of ice cream. The power that's produced by a machine is, again, orders of magnitude larger than the power that's produced by people. A typical healthy young man can produce less than 200 W for a long time. A 5 hp lawn mower engine produces 3,728 Watts as long as the tank has gas.
Within a city or town that grew in the industrial era, roads are shaped by geometry and plans, because machines make it possible to shape the landscape, and there's a reciprocal relationship between the machines: the trucks and cars and bulldozers, and the roads. That is the roads must be large enough to carry a truck, because the trucks must be large enough to carry the machines to build the roads.
However, the human imposed geometry generally disappears at the city limits, and the roads linking cities and towns are more like deer trails.