Elevated corridor not green, finds study

The proposed 102.04-km elevated corridor in Bengaluru city will increase vehicular pollution and raise traffic congestion by 2030, a Sustainability Study on the project by an Indian Institute of Science (IISc) mobility expert has found. Instead, a Metro rail built along the same alignment can be a viable alternative as it actually reduces emissions.

Conducted by Dr Ashish Verma, associate professor, Transportation Systems Engineer, IISc, the study compared two scenarios: Scenario 1 (S1) with the elevator corridor in place by 2020, and Scenario 2 (S2) with no corridor but a Metro rail built along the same corridor.

The technical analysis concluded that in 2030, the per capita emissions for carbon dioxide (CO2) increased by 8% for S1 scenario, while it showed a decline of 26% for S2 with a Metro system. The readings were in comparison to Business As Usual (BAU), a scenario without the elevated corridor in 2020.

From a congestion perspective, the findings were this: “The scenario shows the corridor attracts traffic from all directions, reducing the level of congestion on connecting roads and increasing congestion on the corridor.”

Here’s why the emissions spiked, as Verma analysed: “The construction of the elevated corridor has increased the Vehicle Kilometres Travelled (VKT) because of the commuters trying to reach it from every direction, thereby increasing the emissions,” the study noted.

However, construction of Metro rail leads to a shift away from all private modes of transport, reducing VKT. This, in turn, reduces emissions.

It was found that for the year 2020, emissions of pollutants carbon monoxide, HC, NOx and CO2 increased by 3% for the scenario with the elevated corridor. It reduces by 5% for the second scenario with Metro rail, when compared to BAU. Analysed for the year 2030, the study observed that the emissions of all pollutants increase by 4% for S1 scenario (with corridor) and decrease by 7% for S2 scenario (with Metro) compared with BAU.

In terms of total system travel time too, Metro rail fares far better than the corridor. Due to high speeds on the elevated corridor, there is an 8% reduction in the total travel time. But the travel time reduces by a substantial 40% for Metro, when compared with BAU 2020, says the study.

The technical details of the elevated corridor were sourced from the detailed feasibility report (DFR) prepared by the Karnataka Road Development Corporation Ltd. These were digitised and added to the existing road network for further analysis.

The study incorporated only two-wheelers, cars and buses as the DFR had stated that only these would be allowed.