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Bus Priority Strategies and Impact Scenarios Developed on a Large Urban Area

European Union
Complete with results
Geo-spatial type
Project Acronym
STRIA Roadmaps
Transport mode
Road icon
Transport policies
Transport sectors
Passenger transport


Background & Policy context

All the 3 'users' cities (Genoa, Southampton and Toulouse) and the two industrial 'suppliers' (Elsag and Siemens) involved in PRISCILLA have gained a great deal of experience in bus priority also being involved in several EU R&D projects (PROMPT, EUROSCOPE, INCOME, CENTAUR, QUARTET PLUS, ANTARES, MOBISERVICE...). However, at the beginning of the project bus priority couldn't be considered fully mature in large urban areas (100-400 buses, 80-150 intersections, city centre and suburbs,…). The project is about bus priority in a centralised environment linking the two control systems (Urban Traffic Control for trafficlights control and Automatic Vehicle Monitoring for bus fleet management) taking into account the different individual strategies that can be implemented in the two control centres.


Starting from the state of the art, the scientific and technological overall goal is the demonstration of the benefits of best practice adoption of wide network bus priority strategies. More particularly, the aim is to boost the take up of existing bus priority technologies and methodologies / strategies (practices and processes) by developing them from small scale to wide networks and to produce and disseminate the lessons learnt about best practice adoption of wide bus priority systems.

The operational goals are the following:

1. To define PT priority control strategies, to be tested and adapt to the technological and organisational issues raised by the extension of the systems currently validated on a small scale to a wide city area. The effects of a generalised management of the priority functions on the traffic in a dense public and private transport network cannot be foreseen without due experimentation and, certainly, may be very different from the targeted ones, especially regarding the compromise between benefits for public transport and penalisation of private transport. Advanced priority control strategies have been defined and adopted, based on existing infrastructures and technologies, in order to optimise bus operations for complete bus routes and for the network as a whole.

2. To test different control objectives and to evaluate the main impacts of the related strategies (in terms of bus commercial speed, bus punctuality, private car travel time, acceptance of the professional users, and socioeconomic analysis). The mean to achieve the testing of the control objectives is the realisation of the measurement phase, in which after the definition of objectives (i.e. collecting data without bus priority, decreasing travel time, maintaining timetables at the main stop points,…), related strategies would be implemented on wide networks with a high number of junctions and buses and very close intersections. Measurements in Southampton have been realised by simulation modelling over the same network segments, providing results compatible with the field trials (impacts, evaluation criteria, etc.) but including also testing of a wider range of scenarios and priority control strategies. The evaluation of the related effects and impacts has been reached through a common evaluation plan, ensuring a consistency in impacts measured, even if the timing of the trials and the measurement methods might vary between sites. Existing automatic data recording facilities in t


PRISCILLA is originally a 20-months project, then extended to 23 months, with a specific focused experiment (Measurement phase). The workplan has been split into six different workpackages:
WP1 - Project Management,
WP2 - Current state of the art,
WP3 - Technological and organisational preparation,
WP4 - Measurement,
WP5 - Assessment and Evaluation,
WP6 - Dissemination & Use.

WP1 and WP6 (Project Management and Dissemination) were horizontal activities covering all the life cycle of the project.


PRISCILLA started with the preparation of the first deliverable D1-Presentation of the project in which the project is briefly described in order to let the overall work plan objectives clear also to non specialists.
Following D1, WP2 – Current state of the art, analysed the experiences of the introduction of bus/tram priority systems in European cities, giving a first input to the best practice guide and to the evaluation and measurement plan through its deliverable D2 – PT priority state of the art review.
The WP5 – Assessment and evaluation, included all the activities related to the validation of the applications, producing a first deliverable at the beginning of the project D3 – Evaluation plan, containing the measurement plan, and a second deliverable after the trials D4 – Evaluation results, that would be one of the main output of the project.
The WP3 - Technological and organisational preparation, covered all the adjustments (i.e. extension of radio network, hardware and software adaptation, definition of all the parameters, technical validation of the systems…) needed to put in practice the measurement plan (6 months trials) covered by WP4 – measurement phase in which different strategies have been tested following the same methodological approach, including the simulation activities in Southampton.
The other horizontal activities in the work plan is WP6 - Dissemination & Use, that has been carried on all over the life cycle of the project, producing, at the end of the project D5 - Best practice for PT priority in Europe and D7- Technology Implementation Plan (TIP) indicating exploitation intentions and containing a transferability analysis. D6 - Final Report covered all the work, objectives, results and conclusions on the project.


Parent Programmes
Institution Type
Public institution
Institution Name
European Comission, DG Information Society
Type of funding
Public (EU)


The main achievements coming out from the project derive from the main deliverables (state of the art review, evaluation results and best practice guide) and from the broader dissemination activities in CEEC.

State of the art review:

Buses play a key role in public transport provision, and their ability to transport high volumes of passengers justifies the provision of priority relative to private traffic. This review has demonstrated that there is substantial evidence of the effectiveness of bus priority across a range of applications. In this situation, many cities with limited applications of bus priority will wish to expand city-wide, whilst other cities without bus priority may wish to procure a system. Bus priority can be achieved through a variety of techniques, including segregated systems, traffic management and priority at traffic signals. A wide range of system architectures is being used for bus priority in cities around the world. There is a clear trend for an increasing use of Global Positioning System (GPS) technology to perform the bus location function. GPS provides a potentially cost-effective and flexible solution for bus location. This review has indicated that Europe is leading the way with advanced, integrated systems for bus priority at traffic signals, and the systems being deployed/evaluated in PRISCILLA are at the leading-edge of those available. It is noted from the review that most cities are extending their bus priority systems incrementally, using local priority actions, albeit sometimes controlled by UTC. There is little evidence of network wide strategic approaches being taken, as proposed in PRISCILLA.

A wide and expanding range of system architectures has been identified. A comparative review is therefore proposed of the options identified, to draw out the relative merits of each option in different circumstances and to address the issue of standards and transferability. There is a wide range of reported results of system performance/impacts. Factors such as system attributes, strategy selection and application context could contribute to recommendations for the selection process for systems, strategies and sites. It has become apparent in this review that different institutional and operational 'models' which apply to different cities can significantly affect the implementation options and commitment to bus priority.

Overall, the review has reinforced the importance of PRISCILLA, in taking a network-wide view of bus priority, rather

Policy implications

Concerning implementation and evolution of EU policies, PRISCILLA is clearly contributing to the key challenge about how to reconcile the increased demand for transport with the need to reduce its impact on the physical, social and human environment. It is therefore clear that PRISCILLA helps the European Union to further develop and implement the objectives of the Common Transport Policy and those of national transport policies promoting transport sustainability from an economic, social and environmental point of view and enhancing the efficiency and quality of transport systems and services.

PRISCILLA also supports the Community policy in the field of information technologies and second-generation satellite navigation and positioning systems in the transport sector and other Community policies in such fields as energy, industry, environment, employment in co-ordination with other key actions of the Fifth Framework Programme.

The project also contributes to the EU policy of sustainable mobility by enhancing the attractiveness and accessibility of more sustainable transport modes such as public transport and by enhancing efficiency and quality of the public services by the improvement of the overall cost-effectiveness of transport operations and of the related telematics infrastructures.

The massive increase of demand for travel has led to an increasing congestion; this trend will be continuing with no chance of the supply of road space necessary to meet this demand; new innovative solutions have to be found to maintain the objective of sustainable mobility while reducing energy consumption and air pollution in European conurbations for instance trying to adapt the traffic space to the expected demand with the help of telematics technologies.

PRISCILLA addresses the aims of the EU social objectives in terms of improving quality of life, protection of the environment (saving energy), industrial competitiveness, employment opportunities and cost-effectiveness of public money.

The adopted bus priority strategies on large urban areas can significantly reduce PT travel time and, due to the fact that it has been demonstrated that modal shift in favour of Public Transport is substantially influenced by travel time, deploying proper strategies on large networks could encourage modal shift in favour of Public Transport.

Industrial competitiveness is enforced by the adoption of best practice bus priority strategies both for system integrators and for single product / technolog


Lead Organisation
EU Contribution
Partner Organisations
EU Contribution


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