But this box-pushing work stopped a few months ago following instances of subsidence. After trying ways to strengthen the soil, RVNL engineers concluded cut-and-cover was the only viable method to build the tunnel, which would involve excavating a trench, building the tunnel within it and then, covering it with soil or a roof slab.To carry out the above method, the road from the airport towards VIP Road will have to be dug up. Asked by Airports Authority of India, RVNL conduct a survey and shared it with police. On studying the report, Bidhannagar Police turned down the plea to divert traffic from where the airport signboard now stands through a 1.3-km stretch. According to the diversion plea, vehicles would have been diverted to airport gate No 2.5, from where they would have taken the airport road to airport gate No 1 and then VIP Road. “The vehicles from the airport would have passed through airport gate No. 2.5 on Jessore Road before meeting VIP Road,” an official said.But Bidhannagar Police said the data from the survey indicated that the traffic volume at the crossing of airport gate No. 2.5 would be 2,649 passenger car units (PCUs) an hour, spread over 24 hours, against the hourly 2,400 PCUs stipulated by the Indian Road Congress. Traffic volumes at the airport gate No. 2.5 would cross 4,000 PCUs an hour in the peak period, far more than the recommended capacity, said an officer. Pointing out that the proposed traffic diversion would lead to the tail of a traffic jam reaching as far as Dakshineswar and Madhyamgram in peak hours, police said it would delay flyers headed to the airport from the northern fringes and also those leaving the airport.
