The number of cars on the world’s roads is expected to reach two billion by 2040, significantly increasing pollution and congestion levels in urban areas.
Now researchers at Nottingham University have developed a concept to alleviate environmental and traffic problems associated with the greater use of vehicles, based on a network of subterranean roads.
Unlike tunnels, which can be difficult and expensive to build, particularly over large distances, the idea would be to dig channels within the ground, several metres in depth, according to Prof Saffa Riffat, chair in sustainable energy at Nottingham’s faculty of engineering, who has developed the idea alongside research fellow Prof Yijun Yuan, a specialist in mining engineering and sustainable energy.
The pair have also recently unveiled plans to build underground farms within the disused tunnels of depleted mines, as well as deep sea farms within floating containers, and deep farms within shafts dug into the sand in desert regions.
“Compared to building tunnels, it would be much easier to create a channel in the ground and put a prefabricated surface road on top, allowing you to have twice the area for vehicles to travel on,” said Riffat.
Deep roads would not be affected by weather conditions such as snow, ice, wind and rain, increasing safety and allowing cars to maintain a steady speed, improving their fuel efficiency.
The surface road above could be limited to lightweight, environmentally-friendly forms of transportation such as bicycles and electric vehicles, while petrol or hybrid cars could travel within the channel, said Riffat.
This would increase safety for pedestrians and cyclists, and reduce noise pollution in urban areas, he said.
“It would also mean we could capture the pollutants from these vehicles, because you can’t easily capture pollutants once they’re in the atmosphere, but you can capture them from a sealed environment quite easily, using ducts,” he said.
The captured carbon dioxide could then be used in intensive farming, he added.
In hotter environments, evaporative cooling could be used to maintain a steady temperature within the deep roads. A closed water system would pump over the tunnel cover and then flow back into the road walls, which would be covered in a hydrophilic surface.
The deep road system could also include shafts designed for car parking, as well as bicycle and water storage, said Riffat.