Why are black cabs shaped?

It all dates back to 1948 when the FX3 was first released by Carbodies in Coventry and became the first classically shaped taxi with an orange 'for hire' light on its roof. For fleet owners at the time, often buying multiple vehicles at once, they wanted to keep costs as low as possible.

Why is a black cab called a hackney carriage?

Although the origins of the term 'Hackney coach' is unclear, historians suggest that it derives from the French word hacquenée, which roughly translates as a horse suitable for hire. The first Hackney coaches - large and luxuriously trimmed horse-drawn carriages - appeared during the reign of Queen Elizabeth 1.