DACCORD Executive summary


DACCORD

DACCORD is a major international project dealing with dynamic traffic management and control on inter-urban
motorways. The project is carried out by a consortium consisting of 22 institutions (including motorway operators,
universities and consultancies) based in 8 different European countries. The duration of the project is 3 years and the total
budget amounts to almost 6 million ECU.

The objectives of DACCORD are:

To design, implement and validate a practical Dynamic Traffic Management System (DTMS) for integrated and
co-ordinated control of inter-urban motorway corridors
To further develop an open system architecture for inter-urban traffic management.

Within DACCORD the development of a Dynamic Traffic Management System takes place in two complementary ways:

A "bottom-up" approach geared towards practical experimentation with a large number of traffic management and
motorway control tools
A "top-down" approach oriented towards the development of an open system architecture for DTM systems in
general.

The activities carried out within DACCORD cover a very broad range, from development of new methods, enhancement
and/or integration of previously developed tools, to application and evaluation at different sites. The main ingredients of
DACCORD are:

Architecture development.
Advanced traffic surveillance
Travel time estimation and prediction
Co-ordinated control


ARCHITECTURE

The DACCORD System Architecture describes the future integrated system for Traffic Control Centers (TCC's). Traffic
surveillance, travel time estimation and prediction, and co-ordinated control are key functions of this system. The system
architecture provides a guideline for TCC-owners and developers to allow for a smooth migration towards co-ordinated
control in the future.


TRAFFIC SURVEILLANCE

The DTMS developed within DACCORD requires continuous surveillance of the traffic conditions on the entire road
network under consideration. Measurements of traffic flows and speeds are obtained from data collection systems based
on induction loops. In such systems incomplete and partially inaccurate data cannot be avoided. In order to deal with this
problem data qualification and cleaning functionalities are required. DACCORD provides solutions for real-time data
correction, qualification and completion.


TRAVEL TIME ESTIMATION / PREDICTION

Travel times and queue lengths cannot be measured directly by induction loops. They can either be estimated (using
measurements only) or predicted (using measurements and a prediction method). During periods of the day when traffic
conditions are stable estimation suffices. When, however, congestion is building up (or braking down) predictions are
required to obtain realistic travel times. DACCORD provides a range of different methods for travel time estimation and
prediction in real-time, including congestion detection, queue length estimation, capacity estimation, O.D. prediction,
dynamic assignment and macroscopic traffic flow models.


CO-ORDINATED CONTROL

The capacity provided by the available infrastructure can be used more efficiently by traffic operators using appropriate
control measures. Such control measures include: ramp metering, variable message signs, dynamic routing information,
motorway-to-motorway control, speed control, etc.. When multiple control measures (of the same or different type) are
used independently within the same network, interactions may occur and negative results may be obtained. Integration and
co-ordination is required to avoid such antagonistic effects. This is the central theme in the DACCORD control work,
which includes:

Motorway-to-motorway control
Co-ordinated ramp metering (multiple control measures of the same type)
Network level co-ordinated ramp metering
Advanced routing control
Integrated motorway network control (multiple control measures of different types, e.g. ramp meters and variable
message signs used in combination towards one common objective).


TEST SITES

The DACCORD project benefits greatly from the presence of three well equipped test sites (Amsterdam, Paris and
Brescia-Venice), and the commitment of the corresponding responsible authorities. The three site owners share similar
operational objectives and their respective interests, in particular technical solutions and integration issues, overlap to a
great extent. This provides the project with unique possibilities to gain practical operational experience with the tools
involved, and to carry out a comprehensive evaluation.

Participants