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
Cab Gallery which artworks they reacted to. But it had to be a natural discovery." Artists were provided the views and dimensions of the available spaces such as the bottom of fold-up seats (or "tip-up seats"), the exterior of the cab, and limited inside options for free-standing work. Because the cab was also a working London taxi, after each artwork was selected by the curators, approval from the Cab Advertising Committee of the Public Carriage Office was also required. Artwork placed on the exterior of the cab was printed in vinyl the same as per usual advertising procedures. Special receipts were designed,