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

3. 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

4. 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

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

6. 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)

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

8. Traffic Control Centres - TCC Spanish TCC’s structure

9. 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.

10. 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.

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

12. 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

13. 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 theanalysis time interval • RELATED TO THE DATA MANAGEMENT • Data base generation • Querys

14. DATA PROBLEMS: TYPES OF ERRORS • NO DATA RECORD ● Some or no one variable ● Some or no one time period • WRONG DATA RECORD

15. EXAMPLE OF DATA PROBLEM:INCOMPATIBILITY 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

16. % INTENSITY SPEED OCCUPATION 472 vh/h 108 km/h 24% LENGTH INTENSITY SPEED 472 vh/h 108 km/h 4,6 m EXAMPLE OF DATA PROBLEM:INCOMPATIBILITY 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

17. 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

18. 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

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

20. 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.

21. 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)

22. 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

23. 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.

24. 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

25. 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

26. 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.

27. 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.

28. An ITS to prevent Rear Accidents • System Execution

29. Communication System. 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

30. 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

31. Main Results An ITS to prevent Rear Accidents

32. An ITS to prevent congestions • V-31 (13.700 Km) • South Access to Valencia • Congestion: 1.5 hour/day

33. V-31 An ITS to prevent congestions

34. 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’’ > C’ VOP (System) C’ C’’ It is necessary to look for the optimal speed in the system to avoid congestion in C’

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

36. 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

37. 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

38. Thank-you for your attention