Why is there competition?
Roads are the primary way that people connect to the many things that they value. People want connectivity, so people want roads. New roads, however, destroy open space except in the rare cases that new roads are built directly over or under old roads. This means that open space and new roads are in competition with each other. Because roads beget financial rewards and open space does not, generally roads win the competition.
How do roads “destroy” space?
We often hear that space can neither be created nor destroyed; space just is. In some senses that is true, but we are not interested in space that is filled with stuff, but rather in the gaps between constructed things. Roads themselves are constructed things, and nearly all other constructed things are built adjacent to roads.
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So a road often represents the vanguard, with a legion of other constructions to follow—including more roads. With each construction, the gaps between constructions—the de facto open spaces—shrink.
Roads are not equal in their space destruction. A new road built close to an old road squeezes the edge of open space a bit, but a new road that goes from the perimeter of open space to the center, the heart so to speak, does not just squeeze—it penetrates—and it has a substantially greater effect on spaciousness. For explanation of how this works, see What is Space?.
When roads win, who loses?
Open space, even though it may exist on land that is privately owned, is actually a good that is enjoyed by others than the land owner(s). When roads win in the competition with open space, then the many people—present and future—who enjoy or might enjoy the open space are the losers.
What form does open space “enjoyment” take? Perhaps the most universal and direct is the viewshed—the ability to look across a space that is unobstructed by buildings, power lines, vehicle traffic, and the many other things that humans build that block views. This is one aspect of retaining natural landscape beauty, which assuredly is subjective but also has been demonstrated to have a positive effect on mental and physical health. In some places, another important aspect of landscape beauty is preservation of streams, ponds, and wetlands in their natural state; when roads impinge on water features, the water most often ends up confined to a narrow ditch, a concrete channel, or a culvert. Fish, birds, and other wildlife that prefer water or near-water habitat become scarce, so opportunities to view wildlife are lost to everyone.
There is a second loser, which is more abstract to most people: the ecosystems that occupy open space. These are the reservoirs that we draw on for ecosystem services: clean water, gradual drainage of water (in contrast to impervious constructed surfaces, which drain water immediately), insect pollinators, and wildlife that we enjoy viewing. Ecosystems need space—unfragmented space—in order to function properly and endure. This is not a trivial matter; ecosystem services have been estimated to be worth $125 trillion per year or more globally .
There is an extensive literature in the new field of road ecology that illustrates the numerous ways that roads affect ecosystems, and the broad areas over which these effects are observable. See References  and .
The shared loss
The kind of space that we seek to preserve is uninterrupted space. Roads, and the many constructed things that follow from roads, are visual and physical interruptions. These spatial interruptions constitute a loss to both humans and ecosystems.
|What is Space?
Space requires both area and distance.
|Space is a Nonrenewable Resource
Space loss is essentially irreversible, so space inexorably shrinks.
|The Value of Roads
Roads perform valuable services, so people will pay for them.
|Protection from Roads = Protection of Space
…because roads are the first step in space reduction.
|The Tilted Financial Reward System
Road building pays well; space preservation does not.
|Back to: Open Space—Our Vanishing Resource
Overview of the forces behind space loss.