As you settle into a Meru cab, and the driver turns on the meter, an automated voice alerts you to not drink and drive. The message is repeated once more when the meter is turned off. That is Pernod Ricard, the alcoholic beverage company, welcoming you into the world of cab advertising. It’s a mode of advertising that gives brands the opportunity to target a captive audience. And radio taxi companies such as Meru Cabs and Easy Cabs are making the most of it. It’s all very innovative, as the brand managers of chocolate maker Mars will testify.