When a human heart was being loaded into an ambulance at the General Hospital around 6.40pm on Monday, 6km away, at Light House , traffic inspector Uday Kumar’s walkietalkie crackled to life. He had been preparing for this moment.

The ambulance bearing the heart – harvested from a 27-year-old brain-dead man in GH and to be transplanted in a 21-yearold woman in Fortis Malar Hospitals , Adyar – would pass by the intersection he was guarding, in three seconds. For this, he has been here for three hours.

Like him, 25 other police officers were on duty to ensure that the harvested heart reached its destination to save a life by minimizing the transit period. And they did it in style—the organ traversed the 12km stretch in 13 minutes and 22 seconds, between 6.44pm and 6.57pm. A little more than three hours later, the heart started beating in the chest of Hvovi Minocherchomji . Surgeons at Malar declared the transplant a success.

It was as difficult for the traffic police as it was for the surgeons to save this life. From the pilot vehicle, M Selvaraj, an inspector, kept frequently informing the control room about his location. “Field officers at all the 12 junctions received my messages through their walkie-talkies ,” he said. As the ambulance drew near, officers at each junction froze the traffic from other roads.

Officers had to strike a balance between avoiding a traffic pile-up and ensuring the ambulance gets a free passage. “The ambulance could zip across comfortably at 80kmph, and at times it touched 100kmph. There were no traffic snarls. Our experience in forming green corridors worked to our advantage,” said S Sivanandan, deputy commissioner (planning).

The ambulance crossed 12 junctions with the help of 26 police officers. The team had a minor hiccup as they had to go against the flow of the traffic from the in-gate of GH to the signal. “We had to do this to avoid losing time by taking a U-turn. This was also done because holding the flow of pedestrians coming out of Chennai Central, on the opposite side of the road, would have been difficult,” said Selvaraj. The change was made at the last minute.

The traffic police created their first green corridor in 2009, when a heart had to be taken from Teynampet to Mogappair. “Back then, the heart was taken in a police vehicle,” said Selvaraj. This time, a police vehicle went ahead of the ambulance to ensure the road was free of traffic and pedestrians. The traffic police are usually told two hours prior to the organ harvest. “While the convoy is on the move, all signals it crosses turn green. That’s why the name green corridor,” said Karunasagar, additional commissioner of police (traffic).