Saturday, May 31, 2008
Cost of Idling
Idling is an Indian trait (like prolixity). Or so it was believed, in the old days of the 3% 'Hindu rate of growth'. Given our present rate of growth, such beliefs, at least in the West, have taken a back seat. But here I am talking of cars idling - at traffic lights, at intersections, traffic jams, things that are endemic in most major cities today. And which continues to be a problem. In a fascinating post some time back, Suvrat Kher has done a rough calculation on how much the city of Pune wastes as a result of motorised transport idling for just 2 minutes. Just to shock you into reading the article and his calculations, the total fuel consumed in Pune by idling cars, two wheelers and rickshaws amounts to an incredible 19 thousand litres per day! Emissions of greenhouse gases amount to 45 tonnes/day. This works out to about Rs. 500/- per year per average car owner, wasted on fuel, and taken on a yearly basis, his summary gives 7 million litres of fuel wasted correspondingly adding 16,000 tons of CO_2, 17 tons of PM10, 11 tons of SO_x to the atmosphere. The fuel cost itself is about 340 million rupees. His cost estimates are based on August 2007 prices - you need to multiply by about two and a half to get present day rupee figures. If all vehicles in Pune reduce idling time by just one minute per day we would save about 3.4 million litres of fuel worth about Rs. 17 crore annually! This is equivalent - in terms of fuel saved and CO2 emitted - to removing around 18,500 two wheelers or about 9,300 cars from the roads of Pune. Remember, all this is for just 2 minutes of idling per day for every motorised vehicle. Most of us who drive would find this number absurdly small. One could do this calculation for any of the major cities in India if the data is available. However, though its clear that the numbers are enormous, to get a better feel for the numbers, it would have been better if one could find the percentage of fuel wasted per day based on present day daily consumption. Is there a site which would have this number? Or at least the amount of fuel consumed per day in a given city? A rough and ready calculation assuming I drive for say, 30 minutes a day, would give something like a 7% loss at uniform fuel consumption (for a 2 minute idle). Since fuel consumed during driving is considerably more than while idling, this percentage is probably a slight overestimate, though compensated by the fact that most of us spend more than 2 minutes idling. Do read the post, and more important, switch off at traffic lights and long traffic jams.