The National Union of Road Transport Workers is a Nigerian organisation which functions as a mixture of a public transport company, street gang, and a transport worker's union.
The organisation raises fund through several methods, but the largest of these is charging fees - of approximately 20 Nigerian Naira at illegal checkpoints, and from local shop owners.
A large number of the NURTW have been arrested in recent months after a government crackdown on these unregulated fees, after the government embarked on a plan to stop people from collecting dues outside motor parks. These people are known as agberos.
References
National Union of Road Transport Workers Wikipedia(Text) CC BY-SA