The line graph presents the monthly ridership of green transportation usage in a European metropolitan area from 1980 to 2030.
The usage of the subway and tram showed a steady but significant rise over the period, while commuter usage of the bus and bike share experienced a downward trend.
In 1980, the green transportation usage of the subway and tram was nearly 2.5 million and 0.5 million, or half a million, commuters, respectively. Tram usage increased sharply throughout the period, exceeding bus usage in 2020. Meanwhile, subway commuter usage grew to 3.5 million commuters in 2010 and then remained steady until 2020. During 2010–2020, it experienced a rapid surge to 4.5 million commuters.
In the early 2000s, bike share usage was high, but usage was less than 0.5 million commuters in 2020. Then there was growth of two hundred thousand commuters by 2030.
