Many vehicles were later converted to pay-as-you-enter operation in order to reduce the number of staff needed, but they continued to be known as Peter Witt cars.

Philadelphia Rapid Transit ordered 525 cars from 1923 to 1926, while also converting most of their 1,500 Nearside streetcar fleet to center exit models.

Additionally eleven ex-Milan cars can be seen today on the streets of San Francisco, where they operate on the F Market & Wharves streetcar line.

[3] In early 1930s, а group of Soviet engineers from Leningrad headed by designer D. I. Kondratyev visited the United States and, on their return, adapted the American design to the local narrower loading gauge to start local production of the model LM-33 (popularly known as "американка" (Amerikanka, Russian for "an American lady") that was later used in the city for 45 years (in its last decades, together with other tram models), until mid-March, 1979, according to St.Petersburg Museum of the City's Electric Transport.

[4] Besides their continued use in day-to-day service in Milan, San Francisco and (in a rebuilt form) Naples, Peter Witt cars have been preserved in several locations.