"We can't be at every junction all the time and such measures help" said Ramachandra, a traffic police sub-inspector.

BBC: India cardboard traffic police to deter violators

The firm said it opted not to sound the alarm at every junction as it would have proved counterproductive, but said that it planned to add to the initial 100 locations in London as well as expanding to other cities.

BBC: Navevo sat-nav offers cyclist alerts to lorry drivers

The city's 800 traffic police patrol every major junction, as traffic lights do not function properly because of frequent power cuts.

BBC: Nepal film stars teach traffic police politeness