NEW DELHI: A study by IIT Delhi reveals that vehicle speeds had increased 11am onwards during the first phase of the odd-even scheme . The maximum increase recorded was 9%. However, the average speed of vehicles reduced marginally between 6am and 11am at some locations when the road-rationing exercise was undertaken from January 1 and 15.The study, "Evaluation of the effects of the 15-day odd-even scheme in Delhi: A preliminary report", by researchers at Transportation Research and Injury Prevention Programme (TRIPP), IIT-D, also found a high compliance with the odd-even rule at four locations that were observed.This apart, car-flow rates per hour on different roads decreased by 7-9%. There was almost a similar increase in the number of buses and autorickshaws and a significant rise in the number of two-wheelers during the fortnight, the study says. The air pollution benefits were not apparent because of meteorological factors and the authors of the study felt that data from six stations under the Delhi Pollution Control Committee (DPCC) was not enough to analyse the benefits of the intervention.According to the study, car occupancy increased at all locations except one. The speed data was extracted by the team using google maps distance matrix API. It provides real-time travel distance and time between a pair of locations.Despite an overall increase in the speed of vehicles during the period, Dinesh Mohan, a former IIT professor and the lead author of the study, suggested there were no reasons why the scheme should be continued. "Since there is no improvement in air pollution and the impact on congestion is so little and in fact, it also increased at times, there is no reason to continue it other than gaining international publicity," he said.He added that motorcycle use had gone up during the odd-even period, which could lead to fatal accidents. On why the vehicle speeds had reduced in the morning hours, Mohan said people might have started early to avoid the rule that came into force from 8am onwards. The lower speeds could also be linked to higher number of buses, autos and two-wheelers, Mohan said.A recent study by School of Planning and Architecture (SPA) found that the vehicle speeds at most locations had increased from 15 to 26kmph. It further said that the improvement in speed was higher during the non-peak hours and that morning peak traffic volume reduced by 8-16%. It had indicated that people's exposure to air pollution had reduced during the period.But the IIT study said that "it is possible that the decrease in emissions from cars may be offset by an increase in flow of other vehicles," adding that combined PM 2.5 emissions from buses, autos and two-wheelers was estimated to be 20% of the entire the transport sector compared to cars that alone contribute 16% of emissions.While studies by SPA and Central Road Research Institute (CRRI) as well as an evaluation by the SC-appointed Environment Pollution Control Authority (EPCA) have found reduced congestion and pollution exposure during the odd-even scheme, Mohan said such studies needed "technical, rigorous analysis" and his team had "videographed everything" because it's very easy to get cheated otherwise.