Fuel consumption on passing through co-ordinated signalised junctions could be reduced by at least 12 per cent by the use of AUT. AUT is a most cost effective method based on existing equipment. AUT demands the facility to send traffic data from controllers to a central PC and to send an updated time plan data back to the controllers. It has been estimated that in test area the average cost reduction is SEK 1 000 000 per year and junction. The maximum investment cost for an AUT installation is SEK 100 000 per junction. AUT makes it possible for the number of time plans per day to be increased, which in the test area could increase the fuel saving to 15 per cent. Optimised signal control will reduce delay in the signal system. AUT does not directly deal with redistribution of traffic inside and outside the signal system due to the change in delay. By means of a traffic assignment model this effect has been estimated to be of minor importance in the test area and in the outside area. AUT includes the TRANSYT programme. A validation study from before has shown an overestimation of stops. In order to make a control of the validation result a simulation model based on statistical theory was developed for external link simulations. Simulated stops by TRANSYT were significantly higher than simulated by the statistical model. Since the deviation was systematic it was possible to include an automatic adjustment of estimated effects but not in the optimisation process. This may be expected to result in a lack of effectiveness even if output data could be made representative. (Author/publisher)
Abstract