Customized Simulation Modeling Using PARAMICS Application Programming Interface Henry Liu, Lianyu Chu & Will Recker Paramics User Group Meeting February 7, 2002

Overview 1. Presentation Role of API in Traffic Simulation PARAMICS API Development Plug-ins Developed 2. Demo 3. Hands-on Experience Ramp Signal Control API Loop Data Aggregator API Full Actuated Signal Control API

1. PRESENTATION

User Developer Output Interface Input Interface GUI Tools Professional Community Oversight Core Model API Introduction

Introduction (Contd.) API provides users with a functional interface Command- based With GUI With API Data Interface Functional Interface Simulation Program

Introduction (Contd.) function calls: vehicle related.. link related.. and others user-defined programs Main simulation loop Plugins API data Other applications /APIs Role of a typical API functions

Introduction (Contd.)  Customization pushing the limits More on the API…  Plug-and-play environment reusable and generic plugins  API: the “soft key” to the black-box

Why Customize? Incident Detection Intelligent Parking Travel Time Prediction Signal Control Systems Transit Priority Electronic Road Pricing Road Maintenance Scheduling & Monitoring Bus Scheduling Assistance TESTBED

Why Customize? (Contd.) Network Building Performance Measurement Additional Functionality: ITS Elements Basic Functionality: signals etc Customize

PARAMICS API Simulation Loop Overload Functions Override Functions Callback Functions Built-in Functions User Functions

PARAMICS API (Contd.) Access via API At every timestep (or at intervals) When an event occurs in simulation Event triggered by user

PARAMICS API Development A Hierarchical Approach Provided API Library Developed API Library Advanced Algorithms Adaptive Signal Control Adaptive Ramp Metering Dynamic Network Loading ATMIS Modules Data Handling Routing Ramp Signal CORBA Databases Demand XML

Developed Basic API Library Path-based Routing (Para-Dyn) Actuated Signal Controller Time-based Ramp Metering Loop Aggregator Performance Measurement Paramics-MySQL Communication Paramics-CORBA Communication

Modules Developed Actuated Signal Control Plugin Inputs: Signal Timing Plan, including phase sequence, initial green, maximum green, unit extension time and system recall phase, etc. Detectors need to be specified and associated with movements to be activated. Standard Dual-Ring Logic Actuated Signal Coordination Advanced Signal Control Algorithms

Modules Developed Ramp Metering Basic Time-based Module: Input: time-of-day ramp control plan such as 6-9 AM, cycle length 5 sec. Logic: n-cars-per-green Advanced Modules: Demand-capacity strategy Percent-occupancy strategy ALINEA BOTTLENECK ZONE

Utility Plugins Developed Paramics-MySQL Communication Connecting PARAMICS simulation environment with MYSQL database The MYSQL database can be used in the following two folds: API users can store the simulation outputs to database; During a simulation process, MYSQL database can be used for storing intermediate simulation results, such as aggregated loop data, which can be queried by other external API modules at any time.

Utility Plugins Developed Loop Aggregator Input: time interval, smooth factor, detector name Output: MYSQL database or ASCII file volume, percent occupancy, speed, flow, headway

Performance Measurement Plugin Utility Plugins Developed To customize performance measurement for run-time interfacing with other tools such as data mining and signal optimization. MOE: vehicle count, travel time, stopped time, vehicle-spent time in a specific speed range, turn counts from intersections, cycle time, individual phase time etc. Data collected at a detector, node, link, corridor, OD pair or network levels, at specified time intervals, for specific type of vehicles where applicable. Output can be in the form of database, spreadsheet, text file or on-screen reporting.

Wrap up 1. While GUI helps in building a basic simulation network, API helps in customization of various functional aspects of simulation modeling. 2. Plugins provide users with more freedom to interrupt and control simulation processes and hence facilitates overcoming some of the challenges faced in modeling traffic scenarios of the ITS era.

Publications 1.Liu, X., Chu, L., and Recker, W., “Paramics API Design Document for Actuated Signal, Signal Coordination and Ramp Control”, California PATH Working Paper, UCB-ITS- PWP , University of California at Berkeley, Chu, L., Liu, X., Recker, W., and Zhang, H. M., “Development of A Simulation Laboratory for Evaluating Ramp Metering Algorithms”, Accepted for the presentation at TRB Liu, X., Oh, J., and Recker, W., “Adaptive Signal Control with On-line Performance Measure”, Accepted for the presentation at TRB 2002, publication pending for TRR.

2. PARAMICS API DEMO

PARAMICS API HANDS-ON EXPERIENCE

How to Load API 1.Store API files (*.dll) to a directory. 2. Specify the path and name of API in the “plugin” file located in “Plugins\Windows” under the PARAMICS installed directory. 3. Put the required input file in the network directory.

RAMP SIGNAL CONTROL API Basic Time-based Module: Input: time-of-day ramp control plan such as 6-9 AM, cycle length 5 sec. Logic: n-cars-per-green

INPUT FILES FOR RAMP SIGNAL CONTROL API “ramp_control” file 1. “ramp_control” file ramp name detector name control plans … “priorities” file 2. “priorities” file Provides with the action and phase definition ramp signal

“ramp_control” file total number of controlled entrance ramps is XX vehicle-actuated pre-timed controlyes [or no] on-ramp signalXX name XX presence detector XX number of on-ramp lanes XX number of control plans XX from TIME1 to TIME2 AA with BB veh per CC sec from TIME3 to TIME4 AA with BB veh per CC sec

“priorities” file actions 92 phase offset 0.00 sec phase max red phase 0.00 fill all barred except phase max red phase 0.00 fill all barred except from 91 to 93 major

INPUT FILES FOR LOOP AGGREGATOR API “loop_control” file detector count XX gather smoothed data: no output to files: yes name XYZ gather interval HH:MM:SS name X’Y’Z’ gather interval HH:MM:SS

INPUT FILES FOR ACTUATED SIGNAL CONTROL API “signal_control” file 1. “signal_control” file intersection name signal timing plans … “priorities” file 2. “priorities” file Defines what movement can be allowed under each phase of an intersection.

“signal_control” file Node Movement Initial Green Extension Max Green Recall Phase Lanes Right-Turn lanes Detector 1 Detector 2 Detector 3 Detector 4

“priorities” file actions 528z phase offset 0.00 sec phase max red phase 0.00 fill all barred except from 7510 to 7511 minor from 7511 to 7612 minor from 7511 to 7510 major from 7612 to 7614 minor from 7614 to 7612 major from 7614 to 7510 minor Intersection Layout

ENJOY YOUR SIMULATION!