The Punishing Signal

Noise pollution is a serious health hazard in Mumbai, India. It’s estimated that nearly 70% of noise pollution on Mumbai’s roads is caused by car horns. Researchers had confirmed that long periods of exposure to over 85db sound levels can cause hearing loss. Our client Mumbai Police wanted to find effective ways to change the unnecessary honking behaviour of the drivers and ultimately reduce noise pollution.

We conceived an innovative tech-based and experiential idea, “The Punishing Signal” – the more you honked, the longer you’d wait at the traffic light. Together with the Mumbai police, we identified several heavy traffic junctions/crossroads in Mumbai city and installed sensors with decibel meters at the traffic signals. The trigger that changed traffic lights from “Stop” to “Go” was linked to the sensors: when the sound level crossed 85 dB, the signal would reset. The more you honked, the higher the dB, the longer you wait.

While drivers waited, interactive OOH displays linked to the signal pushed messages LIVE, highlighting their bad behavior with a wink and a smile. If drivers wanted the signal to turn green, they’d need to exercise restraint from honking.

When measuring dBs one week prior to installation vs. one month after, Mumbai Police found a 32% decrease in average honking dBs. Mumbai police announced a further roll-out in 10 additional locations, and then to the entire traffic system in the city. As a result, the Punishing Signal was adopted in many cities such as Hyderabad, Bengaluru city, and Indore city.

A video of the installation tweeted by Mumbai Police became a social media rage. With 6.6 billion impressions, it became the Most Liked & Shared social media post in India. International news outlets in more than 35 countries such as the New York Times, The Guardian, CNN, etc. covered it in over 1000 articles. Mumbai Police’s approval rating reached an all-time high.