Development of Capability-Enhanced PARAMICS Simulation Environment

1. Development of Capability-EnhancedPARAMICS Simulation Environment Lianyu Chu, Henry X. Liu, Will Recker California PATH ATMS Center University of California, Irvine

2. Introduction • Microscopic simulation: • a software tool to model traffic system, including roads, drivers, and vehicles, in fine details. • Micro-simulation models • CORSIM, PARAMICS, VISSIM, AIMSUN2… • Micro-simulation applications • Model traffic network • Model and Evaluate ITS • Calibrate / optimize operational parameters of ITS strategies • Develop and test new traffic models, algorithms, control strategies

3. Introduction • Why capability enhancements are needed • Complement missing functionalities of the current model • Modeling and evaluating ITS • How to enhance • Working on source codes • proprietary of a software • API Programming: a practical way for users • API -- Application Programming Interface • Requirement: an API library provided by micro-simulator

4. User Input Interface Professional Community Oversight Output Interface GUI Tools Developer Role of API Core Model API *source: from FHWA website

5. PARAMICS • PARAMICS: PARAllel MICroscopic Simulation • Developer: Quadstone, Scotland • Features: • Large network simulation capability • Good graphical interface • Modeling the emerging ITS infrastructures • API Programming • Purpose of this paper: • Enhancing capabilities of PARAMICS via API in order to better model and evaluate ITS

6. PARAMICS

7. How PARAMICS API works

8. Aspects of PARAMICS need to be enhanced • Path-based Routing (a missing function) • PARAMICS: Link-based routing • Traffic controller: • Actuated signal control (a missing function) • Ramp metering control (functionality enhancement for facilitating ITS modeling) • Real-time traffic information (a missing function) • including the collection and aggregation of loop data and probe vehicle data • Database connection (functionality enhancement) • Performance measure (functionality enhancement)

9. Current framework of enhanced PARAMICS

10. PARAMICS API Development: A Hierarchical Approach

11. Basic modules:Path-based routing • Required for the simulation of driver responses to the information supply and resulting route choice • Logic: specified vehicles follow a given path • Interface function:

12. Basic modules:Full-actuated signal controller • NEMA Dual-ring, 8-phase logic:

13. Basic modules: Ramp metering controller • Operation: n-cars-per-green basis (with n >= 1) • Pre-timed control • Support multiple timing plans • Support HOV bypass • Support the use of ramp detectors for metering control • Interface functions for external algorithm modules to control metering

14. Basic modules: Loop data aggregator • Emulating the real-world loop data collection • Aggregated loop data are used for real-time traffic control and off-line analysis • Inputs: • loop detector name • aggregation interval (typically with 30 second interval) • Outputs: • Data broadcasting to shared memory, accessible through interface functions • Reported to text files or database for performance analysis

15. Basic modules:Probe vehicle • Emulating section travel time data collection through GPS equipped vehicles • Inputs: • Sections of travel time collection • Sample rate of equipped vehicles • Aggregation interval • Outputs: • Aggregated data broadcasting to shared memory, accessible through interface functions • Reported to text files or database for performance analysis

16. Basic modules:Database connection interface • MYSQL: most popular and highly efficient Open Source SQL database • This interface is developed using API functions of MYSQL. This interface allows us to operate the database via our developed PARAMICS API codes. • Purposes of this module: • Storing intermediate data during simulation and simulation results • Exchange data with other API modules / outside programs

17. Basic modules:Performance measures • PARAMICS has strong abilities on the collection of statistics / measurement data • Current difficulties are: • With the increase of network size, the number of links, trips, intersections, and detectors increases drastically • Large amount of data are required to be processed after simulation runs for obtaining expected MOE. • Some MOE, such as on-ramp waiting time, cannot be extracted from output measurement data. • PARAMICS has a restriction on the number of output files to be opened during simulation under WINDOWS version. • Use API to collect some generic overall MOE for evaluating ITS

18. Basic modules:Performance measures • System performance • System efficiency: Vehicle miles traveled (VHT) • System reliability: standard deviation of average OD travel times • Freeway performance • Mainline: average freeway travel speed and its variance • Ramp: total on-ramp delay and on-ramp queue spillback percentage • Arterial performance • Average travel time of an arterial and its variance

19. Advanced modules:How to develop an advanced module

20. Advanced modules:How to develop an advanced module • Interfaces with ramp metering controller • Set a new metering rate:void ramp_set_parameters (RAMP *ramp, Bool status) • Get current metering rate:RAMP *ramp_get_parameters (char *rampNode) • Interface with loop data aggregator: • LOOPAGG loop_agg (char *detectorName) type Ramp { // ramp signal name and location char *rampNode; char *controllerLocation; // ramp control types and parameters int ControlType; float meteringCycle; }; type LOOPAGG { intdetectorIndex; floatAggregationTime; intlane; intg_vol; floatg_occ; floatg_spd; int*vol; float*occ; float*spd; };

21. Developed advanced modules • Signal control • Adaptive signal • Actuated signal coordination • Adaptive ramp metering algorithms • ALINEA • ZONE • BOTTLENECK • SWARM • PARAMICS-DYNASMART • Demand-responsive Transit

22. Sample applications • Signal • Hardware-in-loop, testing 170 controller • Adaptive signal control based on real-time delay estimation • Ramp metering • Evaluating adaptive ramp metering algorithms • Caltrans Freeway improvement projects • I-10 freeway • I-680 freeway • Caltrans’ Traffic Management System master plan • Evaluating potential ITS strategies

23. Current API user groups • UC Irvine • Caltrans: • Transportation planning • Traffic operation • California PATH program headquarter at Berkeley • UC Berkeley • UC Davis • National University of Singapore • Consultant companies: • Dowling Associates • Cambridge Systematics

24. Conclusions • API can access the core models of micro-simulation. • PARAMICS is a good simulation shell that users can replace its algorithms through API. • We enhanced capabilities of PARAMICS and used the enhanced PARAMICS for modeling and evaluating ITS. • The developed APIs have been used by Caltrans and our research & project partners in many projects. • The same enhancement mechanism can be applicable to other micro-simulators, such as VISSIM, AIMSUN2, etc.

25. More information • PCTSS website: http://www.its.uci.edu/~paramics/ • PATH website: http://www.path.berkeley.edu/ • Contact: PATH ATMS Center @ UC Irvine • Lianyu Chu: lchu@translab.its.uci.edu • Henry Liu: hliu@translab.its.uci.edu • Will Recker: recker@translab.its.uci.edu