Metros are of critical importance for mobility, as societies are becoming ever more urbanised. At the end of 2017, there were established metro networks in 178 cities in 56 countries, carrying an average total of 168 million passengers per day. This massive growth is largely to be credited to developments in a few Asian countries which are prioritising this sustainable mode of transport.
metro passengers in 2017
predicted new lines in the next five years
metro lines reportedly under construction by 2018