I see council long-term plans make many mentions of CCTV implementations on buses, bus stations, bus stops and taxi ranks. Safety and security on board taxis would be an obvious use of centrally monitored CCTV. And a huge market. This idea isn't new, some areas were trialling systems 2 years ago.
This article from August 2004:
"Manchester city council and Greater Manchester Police have launched a crime-busting scheme with cameras installed in 19 black taxis and private hire vehicles. If successful, it could be extended to the 2,800 cabs registered in the city."
Most of the early systems took snapshots which were stored on a hard-disk located in the cab. As technology evolves and both communications and digital storage become cheaper, centrally monitored and controlled CCTV becomes feasible in large volume. Modern systems also have real-time emergency and panic alerting to a central control.
There are many small companies in this space which looks ripe for consolidation through acquisition and mergers.