This paper reports how data from SCOOT was used to conduct a `before-and-after' survey of the effectiveness of a SCOOT urban traffic control (UTC) system in Aberdeen, Scotland. Data from the SCOOT model were collected for three one-hour periods (morning peak, midday and afternoon peak) during each of five working days, before and after introducing SCOOT signal control. The data were analysed statistically, using the SPSS statistical package, and then further analysed using a Lotus 123 spreadsheet. The data were collated to give summaries at ten-minute intervals during each period, and summarised to give vehicle flows, delays, congested intervals and stops in each of the periods. The average of these quantities are tabulated for these quantities are tabulated for both SCOOT operation and the previously used non-SCOOT traffic control systems. Statistical t-tests were performed to estimate the significance of differences between these averages. It was found that SCOOT increased total traffic flows by about 5%, decreased average delays by 29% to 43%, reduced the number of congested intervals by about 32%, and reduced the average number of stops by about 1%. It is estimated that average benefits for road users in Aberdeen are likely to be about 4 million pounds per year.
Abstract