Are underground roads the solution for better urban environments?

Traffic congestion has become a critical issue in urban environments as it decreases the quality of life and increases the pollution levels. Would underground roadways resolve this problem?

Currently, despite all the measures that have been established to alleviate traffic, the number of vehicles is constantly increasing. In order to facilitate higher vehicle flows, bigger roads have to be constructed. But, if those roadways are constructed on top of the ground the pollution levels will increase and the living standards will decline.

Over the past years, some countries have trying to tackle the issue by prohibiting the use of certain motor vehicles in the center of major cities, especially in Europe (e.g. Paris, Madrid, Oslo, London, Brussels and Rome). However, banning vehicles from urban areas is not the optimal solution. At the end of the day, those vehicles will take another route, probably traveling a longer distance, to get to their destination.

According to Professor Saffa Riffat who is also President of the World Society of Sustainable Technologies and Fellow of the European Academy of Sciences and Professor Yijun Yuan, an EU Marie Curie Fellow, the construction of road networks beneath the ground (Deep roads) is the unique solution to address the issue.

Such roads would not be achieved with conventional tunneling methods. They would be built by excavating the soil to form a channel just some meters beneath the surface. The sides and the top of the excavation would be covered, creating an underground "box". While vehicles will move inside the box, the top of the ground can be used for other purposes (e.g. parks and squares). The pollution particles can be captured and be removed before the exit to the surface of the ground.

However, some issues need to be resolved to implement the idea. First of all, old road networks must be gradually replaced. Secondly, urban infrastructure such as telecommunication cables, gas lines, sewage pipes and power lines run beneath major urban roads and, therefore, they need to be transferred somewhere else. Last but not least, the cost of such a project would be higher compared to conventional road construction and it would require an enormous investment to fully replace current road networks.

Scientists believe that deep roads should be supported if we wish to improve quality of life in urban environments.