Where We Should and Shouldn't Build Roads in the Future

Humans are going to pave over 15 million miles of new roads in the next 35 years. This map shows where those roads should and should not go.
Many of the world's new roads are being built in Africa where there is significant conflict between economic and...
Many of the world's new roads are being built in Africa where there is significant conflict between economic and environmental concerns.W. Lawrance et al./Global Road Map

Roads are great for agriculture and industry, but they can also be a huge problem for the environment. And more roads are coming, especially to the developing world, where the needs for economic growth and environmental justice are most at odds. To balance these tensions, a team of geographers made a global map they hope will act as a “large-scale zoning plan” for new roads.

They've got their work cut out for them. According to a 2013 study by the International Energy Agency (pdf), humans are going to pave 15.5 million miles of road by 2050. Ninety percent of this is expected to take place in developing countries.

The top map shows environmental value; the bottom economic value.

W. Lawrance et al./Global Road Map

The researchers approached the problem initially by making two base maps. The first rated the world's environmental value pixel by pixel taking into consideration things like biodiversity and proximity to protected areas. Using similar estimations they made another map that showed economic value of future roads based on the agricultural value of the lands they connected. (The maps to the left show each value in isolation.) Then, the researchers analyzed the overlap between the two layers.

The result is a color-coded map of ecological and economic value. Greener pixels indicate more environmental value, while red means there's money in the banana stand. Darker pixels represent potential areas of conflict, where both values are high.

Lacking topographic information and other necessary inputs, these maps don't show the exact route a new road should carve. Rather, the authors believe their maps will give governments and transportation planners plan balanced infrastructure for long-term economic and environmental benefits.

The map below shows the final, global road planning map. The researchers set up a web site, in case you want to check out their data, or just learn more about the future roads around the world.

W. Lawrance et al./Global Road Map