1900s: For 25 years trams dominate every major city in the world. It is the “golden age” of trams.
1930s: The Great Depression of the 1930s leads to the rapid collapse of many systems. The motorbus takes over.
1950s: World War II hastens the decline of trams but ultimately allows for their reconstruction in several European countries.
1970s: Mass motoring leads to major traffic congestion problems as landscapes are torn down and city centers decline. The disadvantages of motorization start to become evident.
1990s: Urban planners search for ideas to save cities from sprawl and economic decline. Light rail is reborn and trams, once again, claim city streets.
Sources: Light Rail Transit Association and International Association of Public Transport.