| The first elements of a traffic information management system
(TIMS) developed and implemented in Abu Dhabi by PB have been quietly
revolutionising this emirate's traffic accident and traffic flow
management. For the first time in the world, touch-screen mobile
data terminals (MDTs) in police patrol cars and motorcycles (Figure
1) along with global positioning system (GPS) receiver inputs have
been linked to an Oracle database with geographical information
system (GIS) mapping and accident analysis software via global packet
radio service (GPRS) over global system for mobile communications
radio data channels. The result is an accident management system
with location accuracy and codified accident data that provides
the means to attain better quality measures for improvement of road
safety.
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Acronyms in Article:
GIS: Geographic information system
GPRS: Global packet radio service
GPS: Global positioning system
MDT: Mobile data terminal TIMS: Traffic information management system |
As if that were not enough, integrated into this platform is a
system of permanent automatic traffic counters and a traffic analysis
microsimulation tool (VISSIM) that provide traffic management capability.
These two initial application groups-accident management
and traffic management- can be linked, giving users many ways
of analyzing data to better understand how adverse flow patterns
cause accidents and vice versa.
PB's work on this three-phase project began in September 2002:
Phase 1. We produced an overall framework for
TIMS and undertook system development and integration of the accident
management and traffic management elements based on international
practice applied in a local context.
Phase 2. We advanced our Phase 1 work into
a working system using our own application expertise and the support
of subconsultant MAPS for the IT system integration.
Phase 3. In this ongoing work that at the time
of writing was expected to commence in early 2006, we will:
- Support on-the-job training and classroom training that has
already taken place in Phase 2.
- Provide system documentation
- Develop a maintenance strategy
- Provide strategic guidance to help our client, the Abu Dhabi
Department of Municipalities and Agriculture, select the best
way to move forward from this important starting point.
TIMS Framework
TIMS was conceived as a system to integrate a number of separate
subsystems-each targeted at a particular transportation function-in
both the technical and functional layers. Figure 2 shows the overall
framework for the TIMS system that was developed during Phase 1.
TIMS' innovation lies in its integration of the separate functions
with their spatial coordinates in the GIS database layer. With this
ability to combine or relate data in ways that have not been possible
from the separate functions, we saw outcomes that were significantly
more advanced than any seen from systems used in previous initiatives
around the world.
Accident Management
Using GPS and GIS Together. A key example of the
advanced outcomes available from integration is the way in which GPS
and GIS have been used together to improve the location accuracy of
accident data collection. Our challenge had been that GPS reception
alone did not provide the accuracy needed to ensure that the cause
of accidents was truly apparent (Figure 3). For instance, knowing
if an accident took place before a turn-out, alongside it or after
it is crucial when distinguishing the combination of road design factors
and driver behaviour that contributed to the accident. Once these
factors are truly understood and the patterns can be established,
a programme can be implemented to reduce accidents through a combination
of engineering, education and, where appropriate, enforcement.
Such accuracy was possible from a GIS system; however, the task
of identifying position with GIS mapping alone (Figure 4) would
be highly cumbersome for a police patrol in the field. With TIMS,
patrol officers can identify their approximate position easily and
quickly by using the GPS data superimposed on the GIS-produced on-screen
map. This second feature enables them to use ready visual references
to identify the location with pin-point accuracy.
A second challenge was to identify the best way to provide GIS data
to the in-car terminals. The two options considered were to:
Provide the data over the GPRS data link
Have the data reside in individual terminals.
The problem with the first option was that communication was very
slow; whilst with the second option, data resident in the terminal
held the danger that GIS updates would be missed on some or all terminals.
The latter approach was adopted, with the concerns about updates being
mitigated by including GIS version checks in the maintenance routines.
Real-Time Driver/Vehicle Verification. A further
example of advanced outcomes lies in the real-time links provided
over the GPRS data channel to the vehicle registration and driver
licensing databases. The information is an important requisite of
the accident reporting system and by drawing down this data in real-time,
patrol officers can complete accident forms far more easily than
before. This capability helps to avoid the gaps and inaccuracies
that often result when form completion is onerous, and the inaccurate
or inconclusive results that such poor reporting can lead to.
Although it is considered still too early to see the benefits for
accident analysis and the measures that follow (data has not been
gathered for a significant enough period), the police patrol staff
has received the new system with tremendous enthusiasm. Additionally,
senior police officials who appeared originally to gain little direct
benefit from the system are now enthusiastic at the improvement
in both the efficiency and effectiveness of their police force.
Improved Traffic Flow
The traffic management application includes:
Permanent automatic traffic counters to provide greater understanding
of traffic flows
VISSIM, a cutting edge traffic analysis microsimulation tool
used for powerful visualization of specific traffic scenarios
in varying conditions.
A great deal of thought was put into the selection of the most
appropriate traffic analysis tool. Other products were considered,
but VISSIM was favored because of its high level of proven supplier
support and provided in-depth visualization. Additionally, the Abu
Dhabi road network is based on the grid model found in Manhattan
(which was a basis for VISSIM development), so VISSIM was especially
appropriate because of its treatment of signaled intersections.
One issue we faced was to be very clear on the objectives. The
impressive visualizations of VISSIM, as with its competitors in
varying degrees, are often reminiscent of leisure/ recreational
products such as SIM CITY, the urban planning video game, or even
PC games such as Transport Tycoon. Such visualization can lead to
over-expectation and can easily cause the illusion that the simulation
tool itself offers real-time traffic management when, in practice,
this is better achieved by the experienced traffic engineer aided
by a good, closed-circuit television system.
VISSIM provides in-depth visualization of the scenario, enabling
"what-if" analysis to produce a bookshelf of solutions
available to an engineer. These solutions are coded to reflect different
road geometries and signal timings, and calibrated to include known
driver behaviour patterns, leading to measures of effectiveness.
The resultant agility with which engineers can respond to events
as their detailed understanding of traffic performance and corrective
measures increases should reap benefits for many years to come.
The actual effectiveness of this approach will not be known for
some time to come, however, which is a drawback with all cutting
edge developments.
Current Status, Future Enhancements
By early November, 2005, the bulk of the system was in operation,
with only the permanent automatic traffic counting systems to be
completed. By about February 2006, this is very likely to be complete,
and we will embark upon our continuing role under Phase 3 (described
above).
The accident management and traffic management elements are only
the beginning, however. Dr. Atef Garib, The Abu Dhabi Department
of Municipalities and Agriculture's Project Director for the TIMS
project, said, "TIMS will form the basis for other subsystems
to be added over the coming years, such as a travellers' information
and guidance system and an asset management system. We are very
proud that, with PB's help, Abu Dhabi is pioneering the introduction
of such advanced integrated applications. Although initiatives of
this kind take a while to produce a visible effect, we recognized
that without action now, the future development of Abu Dhabi was
almost certain to lead to a sudden major increase in traffic problems
and escalating accident figures. We realized, therefore, that it
was essential to be proactive in developing the mitigations necessary
to prevent this scenario before it arrived, rather than as a reaction
when it was already too late."
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Related Web Sites:
http://www.codatu.org/ francais/publications/actes/conferences/codatu11/Papers/khan.pdf
Roy Pemberton became project manager of Abu Dhabi's
TIMS project during Phase 2. He is a multi- disciplinary project
manager with specialist skills in electronic systems. In addition,
he is managing development of PB's portfolio of "mega-project"
project management in Abu Dhabi, managing such projects as Al Raha
Beach Development through its early start phase.
Jerry Mahany has been responsible for the accident
management aspects of Abu Dhabi's TIMS project. He has assisted
in setting up and maintaining a UK local authority's computerised
accident data storage and retrieval system. On other assignments,
Jerry has carried out numerous accident studies and developed on
behalf of the Highways Agency a Road Safety Plan for part of the
M25 in the UK.
Ahmed Ghaly, who has been responsible for the
traffic flow aspects of the project, carries experience in traffic
and systems engineering both in the UAE and in the U.S. Of particular
relevance to Abu Dhabi's TIMS project, he has been responsible for
the introduction of microsimulation tools, and he is an experienced
infrastructure project manager.
Dr. Atef Garib is Head of Studies and Development
in the Roads Directorate at the Abu Dhabi Department of Municipalities
and Agriculture. He has been project director for the department
throughout the project. He is also a professor at universities in
Egypt and North America, and has spent a period as assistant Minister
of Transport for Egypt. |
