1. INTRODUCTION The population of Delhi has grown rapidly from 1.7 million in 1951 to 13.7 million in 2001. The entire city witnessed a high growth of transport demand over the years. The vehicle population has grown from 0 .01 million in 1951 to 3.5 million in 2001 and 4.2 million in 2004. The number of signalized intersections has increased from 466 in 1996 to 600 in 2004. Variety of road based transport modes catering to the transport demand ply in large numbers on the road system. As a result, the traffic and transportation problems are aggravating day by day. These problems are manifesting themselves in the form of increased traffic congestion, increased air and noise pollution, accidents, delays and subsequently wastage of fuel. The consumption of fuel is on the increase due to enhanced trip lengths, shift of modal share towards personalized modes of travel and at signalized intersections (during the stoppage of vehicles during red signal phase). With increasing traffic at intersections it becomes essential to install traffic control devices to regulate the movements through the intersection. Automatic traffic signals are the most commonly used traffic control devices installed at the road intersections. These devices allocate right of way to different approaches of the intersection as per the sequence of phasing with the aim of minimizing the delays and also avoid conflict and chaos due to crossing traffic. When the vehicles are waiting for their turn to clear the intersection, the drivers normally keep the engines of their vehicle on and this result in extra fuel consumption. Small amount of fuel wasted, aggregated over number of cycles per day, number of days per month and number of signalized intersections becomes a huge quantity. 2. OBJECTIVES AND SCOPE OF THE STUDY With this background, the objectives of the study are summarized as follows: (i). Quantification of fuel loss during idling of vehicles at selected intersections. (ii). Estimation of total fuel loss in Delhi during idling of vehicles at intersections. (iii).Estimation of benefits in terms of fuel savings to be accrued by implementing improvement measures. The scope of the study is limited to the signalized intersections only. 3. METHODOLOGY To estimate the fuel loss at signalized intersections in Delhi twelve intersections of varying traffic volumes were selected, which were spatially distributed all over the city, out of which 8 were of heavy volumes, 2 medium volumes and 2 low volumes. The intersections have been identified as low, medium and high with the criteria; low volume intersection <75,000 vehicles per day, medium * Scientist ** Head † Written comments on this Paper are invited and will be received upto 30 th June, 2008. } TPE Division, CRRI, New Delhi E-mail: purnima.crri@nic.in Paper No. 539 ESTIMATION OF FUEL LOSS DURING IDLING OF VEHICLES AT SIGNALISED INTERSECTIONS IN DELHI † MRS. PURNIMA PARIDA * AND S. GANGOPADHYAY** ABSTRTACT The consumption of fuel is on the increase in metropolitan cities due to enhanced trip lengths, shift of modal share towards personalized modes of travel and congested intersections. When the vehicles are waiting for their turn to clear the intersec- tion, the drivers normally keep the engines of their vehicle on and this result in extra fuel consumption. Small amount of fuel wasted, aggregated over number of cycles per day, number of days per month and number of signalized intersections becomes a huge quantity. 12 Representative signalized intersections of varying traffic volume have been selected in this study to ascertain fuel loss during idling of vehicles. In Delhi, 0.37 million kilograms of CNG, 0.13 million litres of diesel and 0.41 million litres of petrol is wasted everyday due to idling of vehicles. Converting these figures into monetary terms, the total losses work out to be Rs.27.25 million per day and Rs.9944.5 million per annum. After the implementation of remedial measures, a total of 67.78 per cent of fuel savings and a 71.12 per cent savings in the economic loss shall be accrued.