Reflecting on the impact of public conveyances in the city of Berlin during the first years of the twentieth century, Georg Simmel wrote,

"The interpersonal relationships of people in big cities are characterised by markedly greater emphasis on the use of the eyes than that of the ears. This can be attributed to the institution of public conveyances. […] Before buses, railroads and trains became fully established during the 19th century, people were never in a position to have to stare at one another for minutes or even hours on end without ever exchanging a word."