INTELLIGENT URBAN TRAFFIC SIGNALLING INFRASTRUCTURE WITH OPTIMIZED INTRINSIC SAFETY

1. INTELLIGENT URBAN TRAFFIC SIGNALLING INFRASTRUCTURE WITH OPTIMIZED INTRINSIC SAFETY Prof. Marius MINEA, Ph.D Lect. F.C. Nemtanu, Ph.D. Stud. POLITEHNICA University of Bucharest ICCCC 2006 – Baile Felix Spa

2. Introduction • What is ITS? ITS stands for “Intelligent Transport Systems”, representing a set of measures undertaken to improve information, safety and seamless flow of transport and traffic. ITS deals with the term “Telematics”, a combination of the technologies involving Telecommunications and Informatics

3. Main ITS components • ATMS – Advanced Traffic Management Systems; • ATIS – Advanced Traffic Information Systems; • CVO – Commercial Vehicles Operations; • APTS – Advanced Public Transport Systems; • AVCS – Advanced Vehicle Control Systems.

4. UTMC Systems • An UTMC system, component of Intelligent Transport Systems, defines a generalised architecture for traffic management and vehicles priority in terms of: • Monitoring/location of Public Transport Vehicles (PTVs), or other type of vehicles; • Road Network Modelling; • Traffic Management Strategy Selection; • Strategy Implementation; • Management of common/historic databases.

5. Adaptive signal control has recently emerged as a viable system control strategy within the United States, Europe and Australia. Long used in Europe and Australia, adaptive control consists of the real-time adjustment of coordinated signal timing parameters as well as independent intersection control to adapt to changing traffic conditions.

6. Benefits of ITS

7. Safety improvement – a major goal of ITS

8. Specific, existing UTMC systems • Specific UTMC systems, such as SCOOT, SCATS, UTOPIA, SITRAFFIC, ITACA are now wide spread around the world and already considered “mature” UTMC systems. • SCOOT – Split Cycle Offset Optimization Technique • SCATS - Sydney Coordinated Adaptive Traffic System • UTOPIA - Urban Traffic Optimisation by Integrated Automation • SITRAFFIC – Siemens Intelligent TRAFFIC system • ITACA – Intelligent Traffic Adaptive Control Agent

9. Using Mathematic Algorithms for Traffic Modeling • Several Traffic models: • Static models – using fixed traffic data, allocated to Origin-Destination matrixes; • Dynamic models – using variable data for traffic flows between nodes of a matrix; • Continuous models – using fluids laws for modeling traffic behavior; • Micromodelling – using time division to describe local traffic behavior;

10. Specific diagrams – traffic demand in a city

11. Specific diagrams Vehicles speed (q) versus traffic density (k)

12. Simplifying the process, the UTMC system measures continuously traffic demand using special detectors. Then, it calculates optimal signaling using several techniques, according to the technology and software. • For example, the traffic models that use fluids flowing laws are represented by a set of mathematical equations; some of these can be solved analytically, some with numerical procedures. In practice, a link between two junctions is divided in several “cells” with a length equivalent to a normal vehicle. Traffic conditions are estimated using time splits of 0.5 to 10 seconds. Information is then distributed to traffic controllers, that actuate traffic lights.

13. Legend: A – Available feature; N – non-available; R – reduced accuracy; P – precision of the models

14. ERRORS VEHICLE DRIVER “IN FRONT” VEHICLE STATUS PERCEPTIONINFORMATION COLLECTION DECISION EXECUTION FEEDBACK REACTION VEHICLE DYNAMICS NEXT VEHICLE STATUS Logical diagram for the Following Vehicle Pattern Model (example)

15. Present state in Romania • There are no important UTMC systems implemented (exceptions are the UTOPIA for 41 “Light metro” line in Bucharest, and the future Bucharest Multisector UTC/PTM/CCTV project for around 100 junctions and 300 buses); • The signalling infrastructure is heterogeneous, obsolete and frequent failures are reported; • There is no a centralised concept in monitoring, control and repair operations for the road signalling infrastructure; • There is no an updated database concerning the field facilities kept at an administrative authority (such as Street Administration) – so as at this moment, if a traffic signal or sign is damaged or missing, there will be a big delay (days) until the authority will be noticed and maintenance will be performed; • The Street Administration required several times a centralised, integrated method/platform for field data acquisition/monitoring of the signalling infrastructure.

16. Traffic controllers SIGNALLING ELEMENTS POSITIONS DATA COLLECTION Human Operators AUTOMATIC FAULT REPORTING Traffic controllers SYSTEM Radio or wired data network OPERATION AND MAINTENANCE CENTRE Maintenance Companies and Operators USERS INFORMATION Traffic participants Road users Media and information distribution centre Designing an ITS platform for the road signalling infrastructure Functional architecture for the Optimised Signalling Infrastructure

17. Specific requirements for the integrated optimised signalling infrastructure • Traffic management systems by definition contain functions for the detection and selection of vehicles and functions associated with the granting of priority; • A very important characteristic of the communications network for these systems is that the delay for any operational data must be strictly controlled; • The communications network is a crucial element in an optimised signalling infrastructure.

18. Specific architectures for priority granting and fault management functions • When the priority strategy is separate and interrupts the background strategy, then there is scope for a variety of architectures. It is possible, but not necessarily desirable for some or all of the priority functions to be logically separated from the background control function. Four groups of architectures are possible: • Centralised UTC and priority functions, centralised fault reporting; • Decentralised UTC and priority functions, centralised fault reporting; • Centralised UTC with decentralised priority functions, centralised fault reporting; • Decentralised UTC with centralised priority functions, centralised fault reporting.

19. Fault reporting • As seen in the above classification, the fault reporting / management function should be always centralised, as this is very important for the good operational status of the system. In all cases, even if there is or there is not a wired communication network link to a management centre, there is a must to have a radio link (or GSM network link) for the fault monitoring function.

20. Specific architectures (1) Centralized control, all functions

21. Specific architectures (2) Decentralized control, all functions

22. It is a known fact that the road transportation is most affected with traffic incidents, casualties, traffic jams and general congestion, due to the large number of vehicles, both private and/or belonging to state agencies or companies. • Implementing ITS in urban transport means introducing mathematic algorithms for traffic optimization, introducing “intelligence” at the street level.

23. Conclusions • Traffic management systems are complex architectures, with core processing equipment that requires sensor data fusion, mathematic algorithms and good communications infrastructure; • Increasing the intrinsic reliability thru specific measures means reducing traffic incidents, environmental pollution and costs for transport.

24. Thank you! www.e-safety.ro www.eltrans.pub.ro UPB-CEPETET Centrul de Cercetare, Proiectare, Service si Consulting in domeniul Telecomenzilor si Electronicii in Transporturi marius.minea@gmail.com marmin@eltrans.pub.ro