SCOOT is a fully adaptive traffic control system which uses data from vehicle detectors and optimises traffic signal settings to reduce vehicle delays and stops. There are a number of basic philosophies which lead to the development of SCOOT. One of these was to provide a fast response to changes in traffic conditions to enable SCOOT to respond to variations in traffic demand on a cycle-by-cycle basis. SCOOT responds rapidly to changes in traffic, but not so rapidly that it is unstable; it avoids large fluctuations in control behaviour as a results of temporary changes in traffic patterns. (SCOOT website)

SCOOT not only reduces delay and congestion but also contains other traffic management facilities. For example, in 1995 a new facility was introduced to integrate active priority to buses [link to bus priority] with the common SCOOT UTC system. The system is designed to allow buses to be detected either by selective vehicle detectors or by an automatic vehicle location (AVL) system. (SCOOT website)

Further information regarding the details (such as the development, how it works, installing, facilities etc.) can also be found in the SCOOT website.

Impacts on demand
SCOOT is in use worldwide and has been shown to give significant benefits over the best fixed time operation. The effectiveness of the SCOOT strategy has been assessed by major trials in five cities (Wood, 1993; SCOOT website). The results from the trials are summarised in the table below.

* Vehicle - actuated

Comparisons of the benefits of SCOOT, against good fixed time plans, showed reductions in delays to vehicles of average 27% at Foleshill Road in Coventry - a radial network in Coventry with long link lengths. In Worcester the use of SCOOT rather than fixed time UTC showed considerable saving which was estimated to be 83,000 vehicle hours or £ 357,000 per annum at 1985 prices. The replacement of isolated signal control in Worcester by SCOOT was also estimated to save 180,000 vehicle hours per annum or £ 750,000 per annum. In Southampton, economic benefit, excluding accident and fire damage savings, amounted to approximately £140,000 per annum at 1984 prices for the Portswood/St. Denys area alone.

Research by Bell (1986) suggests that SCOOT is likely to achieve an extra 3% reduction in delay for every year that a fixed-time plan "ages". Further, the effects of incidents have been excluded from many of the survey results to ensure statistical validity. Since SCOOT is designed to adapt automatically to compensate for ageing and incident effects, it is reasonable to expect that, in many practical situations, SCOOT will achieve savings in delay of 20% or more.

In 1993 a SCOOT demonstration project in Toronto showed an average reduction in journey time of 8% and vehicle delays of 17% over the existing fixed time plans. During weekday evenings and Saturdays, vehicle delays were reduced by 21% and 34%. In unusual conditions following a baseball game, delays were reduced by 61%, demonstrating SCOOT's ability to react to unusual events. (Siemens Automotive, 1995)

In Sao Paulo in 1997 a survey showed that SCOOT reduced vehicle delays by an average of 20% in one area tested and 38% in another over the existing TRANSYT fixed time plans. It was estimated that financial benefits to Sao Paulo as a result of these delay reductions would amount to approximately $1.5 US million per year. (Mazzamatti et al, 1998)

Field trials of bus priority using SCOOT survey were carried out in areas of Camden Town and Edgeware Road in London in 1996. The Camden network consisted of 11 nodes and 28 links. The Edgeware Road site was a linear network consisting of 8 nodes and 2 pelican crossings. The bus routes were surveyed for the periods 7:00 - 12:00 and 14:00 - 19:00. The results show that greater benefits can be obtained where there is lower saturation level. (Bretherton et al, 1996)

Contribution to objectives

[Preferably include Toronto results under case study] [*Surely reduced steps/starts reduces accidents? Any evidence of this?]

UTOPIA (Urban Traffic Optimisation by Integrated Automation) / SPOT (System for Priority and Optimisation of Traffic) is designed and developed by FIAT Research Centre, ITAL TEL and MIZAR Automazione in Turin, Italy. The objective of the system is to improve both private and  public transport efficiency. The system has been fully operational since 1985 on a network of about forty signalised junctions in the central area of Turin. The area also contains a tram line and control of the trams is integrated within UTOPIA/SPOT (Wood, 1993). UTOPIA/SPOT is now used in several cities in Italy and also in the Netherlands, USA, Norway, Finland and Denmark.

The system uses a hierarchical-decentralised control strategy, involving intelligent local controllers to communicate with other signal controllers as well as with a central computer. Central to the philosophy of the UTOPIA/SPOT system is the provision of priority to selected public transport vehicles at signalised junctions and improvements in mobility for private vehicles, subject to any delays necessary to accommodate priority vehicles (Wood, 1993). The French PRODYN system and the German MOTION system have some similarities to SPOT, but have not been used outside their counties (Kronborg and Davidsson, 2000).

The improvements attributed to UTOPIA in Turin have been calculated a previous traffic responsive control strategy rather than against a fixed time system. Benefits of implementing UTOPIA were shown to give an increase in private traffic speed of 9.5% in 1985 and 15.9% in 1986, following system tuning. In peak times the speed increases were 35%. Public transport vehicles, which were given absolute priority, showed a speed increase of 19.9% in 1985 (Wood, 1993).

SPOT was introduced in Scandinavia in the early 1990’s (Kronborg and Davidsson, 2000). In Oslo, Norway, SPOT started to be operated in four intersections with high priority to public transport in 1996. Only traffic parallel with the tram routes was evaluated and had good results (15% reduction in travel time).

UTOPIA/SPOT has been explicitly designed with public transport vehicle priority in mind (Wood, 1993). Buses and LRT vehicles are given absolutely priority at junctions, subject to the accuracy in forecasting their arrival time. In Turin LRT are given higher priority than buses because they have more passengers but extra priority can be assigned on a vehicle by vehicle basis if required.

Gaps and weaknesses

Many papers or reports on UTC systems evaluated only the impact on efficiency such as reduction in journey time, delay and stops compared with previous types of system. However, reducing travel times can increase road capacity, and increasing capacity over a significant area may cause a shift in demand towards car use and increase car traffic volume. The potential for the benefits of UTC systems to be eroded by induced traffic needs to be borne in mind. Relatively little information is available on environmental or safety benefits.