Improving the monitoring quality to Automate ITS Systems

1
Improving the monitoring quality to Automate ITS
Systems

• Enrique Belda Esplugues
• Civil Engineer
• Head of Valencia TCC
• Associate Professor at Valencia Polytechnic
  University

2
Summary

• Introduction
• Traffic Control Centres
• Data Monitoring
• ITS systems to improve road safety
• To prevent rear accidents
• To prevent congestions
• Conclusions

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Introduction

• Dirección General de Tráfico (DGT) is the Spanish
  road authority in charge of traffic management
• The responsibility for traffic competences in the
  Basque country and Catalonia have been
  transferred to the autonomous region
• The DGT has been working in ITS since 1991
  applying new technologies to improve traffic
  flows and road safety
• The DGT is involved in the ARTS and SERTI
  projects
• Project manager in ARTS

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Introduction

• The most important ITS services are focused on
  improving road safety and problems caused by
  traffic incidents
• Preventive
• Integrated system aimed to anticipating dangerous
  situations
• Weather forecasts
• Range detection of slow vehicles
• Incident detection and management
• Systems in charge of detecting incidents once
  they occurred and of managing the consequences to
  minimize them.
• Artificial vision using CCTV cameras
• Systems based on traffic data collection stations
• Management plans

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Summary

• Introduction
• Traffic Control Centres
• Data Monitoring
• ITS systems to improve road safety
• To prevent rear accidents
• To prevent congestions
• Conclusions

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Traffic Control Centres - TCC

• TCCs are responsible for traffic management and
  control on the road networks. The TCC controls
  and manages all the ITS systems installed on
  highways within their competence.
• Spanish TCCs distribution
• Madrid
• Valencia
• Málaga
• Sevilla
• Zaragoza
• A Coruña
• Valladolid
• Bilbao (DT)
• Barcelona (SCT)

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Levels of Traffic Control
Traffic Control Centres - TCC
Control of Accesses to Large Cities
Construction of TCCs
Level 1
Control of the Inter-urban Road Network
Level 2
Control of Local Areas with Traffic Problems
through Local Management Centres, accountable to
Traffic Management Centres
Level 3
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Traffic Control Centres - TCC
Spanish TCCs structure
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Traffic Control Centres - TCC

• The TCC have different operational procedures.
  These operational procedures can be structured in
  three layers
• Daily demand requirements represents the
  activities developed by the TCC once specific
  situations (incidents, congestion, etc) have
  occurred.
• 1st Automation phase The ITS equipment installed
  in the center is fully integrated and allows the
  automatic development of traffic strategies such
  as travel times, incident detection.
• 2nd Automation phase Full system automation. It
  includes not only traffic systems (monitoring,
  information, etc) but also other systems related
  to traffic behavior.

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Traffic Control Centres - TCC

• The deployment of 2nd Automation phase implies
  the homogenization and standardization of all
  equipment and systems installed for a suitable
  integration in the TCC.
• DGT promotes and presides the Committee 4 of
  AEN/CTN 135 (Spanish standardization organism)
  that include all technical workgroups to study
  and draft the different Spanish regulations that
  must be fulfilled by all the traffic management
  systems installed in the Spanish roads.
• DGT also participates in the European traffic
  standardizations committees.

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Summary

• Introduction
• Traffic Control Centres
• Data Monitoring
• ITS systems to improve road safety
• To prevent rear accidents
• To prevent congestions
• Conclusions

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PROVIDED DATA

• The Traffic Data Capture Stations provide1
• Intensity
• Average Speed
• Occupancy
• Traffic Direction
• Interval between vehicles
• Vehicles classification (length, speed)
• 1.- Usually, in time intervals of 1 min, 15 min
  and 60 min

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DATA PROBLEMS ORIGIN OF ERRORS

• RELATED TO THE DETECTION SYSTEM
• Wrong location (other sources interference, near
  metallic mass,)
• System Malfunction (loop cut, deterioration for
  the use, environmental/weather conditions,
  electricity supply problems,)
• System Precision
• Communication failure (dead line, electricity
  supply problems, receiver problems)
• RELATED TO THE PROGRAMMING to obtain traffic
  representative variables
• Programming criteria
• Algorithm development
• Selection of the analysis time interval
• RELATED TO THE DATA MANAGEMENT
• Data base generation
• Querys

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DATA PROBLEMS TYPES OF ERRORS

• NO DATA RECORD
• ? Some or no one variable
• ? Some or no one time period
• WRONG DATA RECORD

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EXAMPLE OF DATA PROBLEMINCOMPATIBILITY WITH THE
VALUE OF THE RECORDED TRAFFIC VARIABLE

• The variables intensity, speed, occupation
  and average length are related through the
  expression
• OCCUPATION

DENSITY
l type vehicle length s safety distance
/distance between vehicles tl spent time of the
vehicle to go across the loop ts time between
two consecutive vehicles over the loop
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EXAMPLE OF DATA PROBLEMINCOMPATIBILITY WITH THE
VALUE OF THE RECORDED TRAFFIC VARIABLE

• In some cases, the occupation percentage value
  recorded is incompatible with the other traffic
  variables

AVERAGE LENGTH OF THE VEHICLE 54,9 m

OCCUPATION 2

• CONSEQUENCE The errors in the record of the
  occupation variable are translated as errors in
  the classification of the traffic states used by
  the DGT

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PROPOSAL OF PROBLEMS SOLUTION

• Related to the data detection systems
• Included in general tasks of road maintenance
• Verification of the location and general state of
  the system
• Verification of the signal emission and presence
• Verification of the communication with the TCC
• Related to the programming
• Revision of the criteria to transform the
  electrical impulse to traffic variables
• Influence Analysis of the time interval period
  selected

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PROPOSAL OF PROBLEMS RESOLUTION

• Related to the data management and report
  presentation
• Data base revision
• Query systematization
• In the reports generation
• Replacement of punctual errors of intensity and
  speed
• Auxiliary table with updated historical data
• Previous and following intervals values to the
  failure point
• Temporary distribution graph about road traffic
  and the AADT value

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Summary

• Introduction
• Traffic Control Centres
• Data Monitoring
• ITS systems to improve road safety
• To prevent rear accidents
• To prevent congestions
• Conclusions

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An ITS to prevent Rear Accidents

• Rear accidents taking place on motorways are
  usually due to
• Overtaking areas with huge speed differences
• End of slow lanes
• Congestion
• These situations could arise in several sections
  of the road network. The DGT, in order to prevent
  motorway accidents, has developed an automatic
  system to prevent rear accidents.

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An ITS to prevent Rear Accidents

• The system presented is installed in two mountain
  passes with a high rate of rear incidents and
  casualties
• the Buñol mountain pass (5 km), on the A-3
  motorway
• the Carcer mountain pass (4 km), on the N-340
  motorway
• These two road areas present
• High accident rate (Carcer pass there were 9, 5,
  11, and 6 accidents from 1996 to 1999
  respectively)
• Similar characteristics
• Hilly road sections
• HGV itineraries
• usually bad weather conditions (mainly fog)

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An ITS to prevent Rear Accidents

• The development of the systems was structured
  into five phases
• Study of the roads involved and the road traffic
  behavior.
• Equipment distribution, both detectors and
  signals.
• System implementation.
• System architecture
• Validation

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An ITS to prevent Rear Accidents

• Previous traffic studies
• Definition of traffic characteristics Density,
  segment capacity, flow rates, percentage of heavy
  vehicles, mean speed by lane and segment.
• Definition of conflictive points and areas
  vulnerable to accidents. Also a detailed study of
  accidents occurring in each area was conducted.
• Definition of lineal speed functions
  (space-time). These functions are used to define
  the precise instant of the accident and the
  theoretical point where the slow vehicle is hit.

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An ITS to prevent Rear Accidents

• Equipment distribution
• The criteria for placing the equipment are
• Each segment must have at least one detector and
  one signal
• There are intermediate detectors and signals to
  cover all the road network
• The maximum distance between detectors is 600 m.
  in homogeneous sectors and 400 m. in the rest.
• The signals are located 100 m. after the detector
  downstream

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An ITS to prevent Rear Accidents

• Once the studies were carried out, the road area
  is divided into homogeneous segments to place the
  road equipment

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An ITS to prevent Rear Accidents

• The equipment installation in some segment was
  difficult as a viaduct has to be crossed. The
  problems were overcome using magnetic detectors
  under the viaduct instead of the traditional
  loops and installing the signals in the pillars.

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An ITS to prevent Rear Accidents

• The system has been enforced with a variable
  message sign (VMS) installed at the beginning of
  the mountain pass. The message advises drivers
  that they are entering a hazardous area.

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An ITS to prevent Rear Accidents

• System Execution

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An ITS to prevent Rear Accidents

• System architecture
• The system is made up of the following elements
  
• Traffic data capture stations
• Signaling subsystem,
• Local and central control system

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An ITS to prevent Rear Accidents

• System validation
• The system validation was developed from
  different points of view
• Individual equipment functioning
• Traffic detection (loops and magnetic detectors)
• Communication system and the response times.
• General system.
• Capacity to detect problematic situation
• False positives and false negatives
• Processing time to forecast the incident.
• Efficiency of incident reduction
• Evolution of accidents is continuously studied

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Main Results
An ITS to prevent Rear Accidents
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An ITS to prevent congestions

• V-31 (13.700 Km)
• South Access to Valencia
• Congestion 1.5 hour/day

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V-31
An ITS to prevent congestions
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An ITS to prevent congestions

• Optimal Speed on V-31

• Analysis of the unfavorable road section
• (C, C, C) Capacities
• VOP Optimal Speed

C
C C
gt C
VOP (System)
C
C
It is necessary to look for the optimal speed in
the system to avoid congestion in C
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Summary

• Introduction
• Traffic Control Centres
• Data Monitoring
• ITS systems to improve road safety
• To prevent rear accidents
• To prevent congestions
• Conclusions

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Conclusions

• ITS systems are a suitable tool for traffic
  management and control and improving traffic
  flows and road safety.
• The integration of all ITS in the TCCs allows
  road managers to develop more complex systems and
  services.
• The development of ITS and their operation should
  be undertaken taking into account some quality
  levels that guarantee the development of the most
  adequate and control management strategies.
• The evaluation of the systems should be carried
  out in all phases
• Design
• Installation
• Exploitation

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• What best practice cases can be identified?
• To verify real data with measured data and the
  way we obtain them.
• What specific aspects can be regarded as best
  practices?
• To improve communication, algorithms and
  historical traffic data.
• To get better road equipment maintenance
• Are the best practices to the country in question
  to a certain region or globally?
• Globally

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Thank-you for your attention