Paddywagon

A police van (also known as a paddy wagon, patrol wagon, Black Maria or police carrier) is a type of vehicle operated by police forces. Police vans are usually employed for the transportation of prisoners inside a specially adapted cell in the vehicle, or for the rapid transportation of a number of officers to an incident.

Early police vans were in the form of horse-drawn carriages, with the carriage being in the form of a secure prison cell. In the modern age, motorised police vans replaced the older Black Maria and paddy wagon types as they were usually crudely adapted for accommodation of prisoners.

The need for a secure police van was realised when prisoners who were resisting arrest needed to be transported. The concern, was that if transported in a conventional patrol car, the prisoner may attack the officers during the journey.

To combat this, police vans were designed with a fixed steel cage in the rear of the vehicle effectively separating the prisoner from the officers.

The precise origin of the term is uncertain and disputed, though its use dates back to the 1800s. "Paddy" however is a slang term for an Irish person used in the English speaking world, but it is now in decline as it is considered an improper term. (Irish themselves may still use it in an affectionate way but caution should be exercised.)

There are three theories as to how the term originated.

Most of the police vans in the UK have caged sections to keep the occupants apart from each other.

These vehicles were usually painted black or a very dark blue. In the United Kingdom, Ireland, New Zealand and the United States, a police wagon was also sometimes called a Black Maria (/məˈraɪ.ə/ mə-REYE-ə). The origin of this term is equally uncertain. The name Black Maria is common for race horses beginning with an 1832 appearance in Niles Weekly Register (Oct. 10) and then again in Colburn's New Monthly Magazine and Humorist (1841). The OED lists the first usage as the Boston Evening Traveller from 1847 which mentions them as a new type of wagon. An example from Philadelphia was published in 1852.Brewer's Dictionary of Phrase and Fable suggests the name came from Maria Lee, a large and fearsome black keeper of a sailors' boarding house who the police would call on for help with difficult prisoners. The French detective novel Monsieur Lecoq, published in 1868 by Émile Gaboriau, uses the term Black Maria when referring to a police van.

...
Wikipedia