The metro system of future megacities

Abstract

The recent quick urbanisation process has led to a situation where metro systems are no longer able to offer the necessary speeds to cover the ever increasing distances travelled. This reinforces the vicious circle that promotes private mobility and threatens the sustainability of cities. Even though metro systems can achieve higher top speeds than permitted on roads, their main disadvantage lies in the coverage paradox: when stations are close together, the time to walk to stations is short but the speed in the metro is also reduced for stopping more times. Conversely, if stations are far apart for higher speeds on the line, the time to access stations is also increased. Consequently, a journey using the metro always takes more time than it would on private modes. Using a systems engineering process, this research proposes a novel operational model where autonomous vehicles stop in different patterns at stations along a line. These vehicles travel in convoys instead of trains and are controlled by vehicle-to-vehicle communication similarly to those developed for automated highways. Simulations show that this strategy can simultaneously reduce by half the time to access stations and increase by 130% the average speed on the line, thus shortening journey times by up to 45% compared to conventional operations. Moreover, capacity is also increased by 30% compared to the busiest lines in operation. In conclusion, the model can meet the speed requirements of megacities, while increasing the capacity of systems to cope with the demographic trends of the twenty-first century.