The delay suffered by traffic in an urban area can be reduced by coordinating adjacent signals on fixed time plans. Plans that minimise delays may be derived by an offline optimisation method such as transyt. This method can be extended to predict the fuel consumed within a network of signals as a function of the distance travelled, the total delay time and the number of stops. the calibration and use of transyt to minimise fuel consumption is described. Transyt predicts that, in central urban areas, a saving in delay that reduces journey times by, say, 10 per cent is likely to save from 6 to 8 per cent of the fuel consumed. Transyt has also been used to derive fixed time plans that minimise fuel consumption rather than delay. When tested in glasgow, an additional fuel saving of about 3 per cent was both measured and predicted. This fuel saving is estimated to be worth £75000 per annum within the network of 91 signals in central glasgow. The results in glasgow may not be typical of other cities but the transyt method can be used elsewhere to estimate the benefits on fuel consumption of signal coordination. (Author/publisher)
Abstract