Hackney carriage which a taxi may operate and include regulating the taximeter (not compulsory until 1907), the maximum age of the taxi (not more than 15 years), advertisements and the turning circle of . As part of the Transported by Design programme of activities, in 15 October 2015, after two months of public voting, the black cab was elected by Londoners as their favourite transport design icon. In London, hackney-carriage drivers have to pass a test called The Knowledge to demonstrate that they have an intimate knowledge of the geography of London streets, important buildings, etc. Learning The Knowledge allows the driver
Checker Taxi Markin, who subsequently acquired another one-third in the company from Parmelee, thus taking control of both Parmelee and Yellow Cab. In 1940, Parmelee (including Yellow and Checker Cab) became the largest cab company in the United States. Prior to selling the Yellow Cab company, Hertz had sold his taxi-cab, truck, and coach manufacturing arm in 1925 to General Motors. GM wanted to sell part of the acquired business and made an offer to Markin, but Markin declined. Rather than eliminate the capacity of Yellow Manufacturing, General Motors entered the taxicab business in New York City as Terminal Taxi Cab. General