Hardware-In-the-loop Traffic Simulation in Florida Ken Courage Seokjoo Lee University of Florida Transportation Research Center

A Project Sponsored by the Florida Department of Transportation  Investigate the potential uses of the CID as a traffic engineering tool  Develop an awareness of this tool among operating agency personnel  Develop guidelines for future deployment

Project Organization  Six CID units have been purchased to support training and experimentation by interested agencies.  A series of workshops will be presented at various locations in Florida to explain the fundamentals of traffic models with an emphasis on hardware in the loop simulation features.

 The CID units will be offered to interested agencies to deploy for a specified period (usually one month) to assimilate the technology and to conduct experiments of their own. Support will be provided by the project staff during this period.  At the end of the period, there will be an interview to assess the value of the technology in helping the agency carry out its mission.  The results of the experiments will be compiled to develop guidelines for future deployment.

Tasks  Workshop presentations  Tool development  User projects

Tasks  Workshop presentations  Tool development  User projects

Workshop Objectives When you have completed this workshop, you should be able to: Perform a simulation run on a sample intersection problem Set up a traffic-actuated signal controller for the sample intersection Integrate the controller into the simulation loop Define more complex problems for analysis

Workshop Sessions 1. Introduction 2. Simulation as a problem solving tool 3. Simulating an intersection with CORSIM 4. Adding hardware in the loop 5. Suitcase tester features

Tasks  Workshop presentations  Tool development  User projects

TACSim is an instructional tool that supports the training of students in the basic principles of traffic- actuated signal operations

TACSIM Features NB WB Vehicle arrivals, queuing and departures are simulated following simple rules. Basic traffic- actuated control logic is executed, recognizing user- specified values for the controller settings

Example - Simple Intersection NB WB Both Approaches 1 Lane One way Volume: 600 vph 100% thru traffic Initial10 sec Allowable gap 3 sec Max Green 20 sec Yellow 4 sec All red 3 sec

Simulation Logic  Vehicle arrivals are generated each second from a Poisson distribution.  Vehicles are added to a vertical queue as they arrive.  Vehicles are subtracted from the queue at a rate of 0.5 veh/sec (satflow = 1800 vphg) on the green phase after a 3 second lost time  Simulation time = 1 hour (3600 sec)

TACSim Limitations  Two phase control  Intersection of two single-lane one- way streets (NB and WB)  Through movements only  Vertical queuing (no spatial modeling of queues or car following)

The TACSim limitations don’t compromise its usefulness as an instructional tool for basic principles of traffic-actuated signal operations. It is, however, much too primitive to support any research effort. Several excellent simulation models are available for this purpose.

TACSIM Phase Settings Input Panel The controller settings are entered using linear “slider” controls.

Simulation Displays Vehicle Presence Icon Interval Progress meters Queue Length Meter Elapsed Time Indicator Signal Status Display

Operating Modes  Real Time mode for observing the operation in detail  Fast Forward mode for accumulating measures of effectiveness.

Other Displays Dwell Indicator Icon Queue Size Readout

Measures of Effectiveness for Each Movement (Appended to a file for Spreadsheet Analysis)  Delay (Veh-Hrs and Sec/Veh)  Percent stops  Percent cycle failures  Percent green time and dwell time  Maximum queue length  Percent gap-out and max-out

Sample Exercise  Default actuated controller settings 10 sec initial 3 sec allowable gap 20 sec maximum green 4 sec yellow + 1 sec all-red  Plot the delay per vehicle for the volume range of 100 vph to 700 vph

Sample Exercise

Script Enhanced Suitcase Tester Scripting Functions Static Event Table CID

Recurring Events Enhanced Suitcase Tester Scripting Functions Dynamic Event Table CID Script Event Table Builder Log File

New Commands  Reset  Waitfor (Conditions)  Arrival  Departure  Passage  Include

Tasks  Workshop presentations  Tool development  User projects

User Projects  Level 1: Familiarization and Learning  Level 2: Advanced Applications

Student Level II Projects 1. Comparison of delays under HILSim and ICE 2. Comparison of Single vs. Dual ring control 3. Development of scenarios to demonstrate the suitcase tester script feature 4. Offset intersection with one controller. 5. Implementation of shadowed right turns as protected movements vs RTOR

Pilot Level II Project  Comparison of transition logic between arterial timing programs The City of Jacksonville Traffic Engineering Department Buckholz Traffic

Transitioning, sometimes referred to as “offset seeking”, occurs when a coordinated plan change is implemented such that the controller must proceed from one cycle length to another and/or from one offset to another. During the transition period, coordinated traffic operations can be significantly disrupted as the cycle length varies from signal to signal and as yield points occur in an unplanned fashion. The length of the transition period varies depending on the particulars of the “leaving” and “entering” timing plans, as well as the transitioning mode that has been selected, but typically ranges from a few minutes to ten minutes or so. Transitioning

Common CONTROLLER Transitioning Modes 1. Dwell 2. Percent Forward (or “Add Only”) -- Usually adds about 20% per cycle 3. Short Route -- Usually adds or subtracts about 20% per cycle

CORSIM ICE Transitioning Modes 1. Completed Over One Cycle (Dwell) 2. Completed Over Two Cycles 3. Completed Over Three Cycles

More Differences between CORSIM and Controller Transitioning 1. CORSIM transitions over a single phase combination (typically we would choose 2 and 6) whereas controllers usually transition over all phases. 2. CORSIM will only accommodate transitioning between two non-actuated plans.

More Differences between CORSIM and Controller Transitioning (Con’t.) 4. CORSIM requires the specification of a “minimum cycle time” during transitioning whereas most controllers do not. 3. CORSIM transitioning begins when the first “start of main street green” is reached after the plan change- point whereas controllers typically start transitioning when the first yield point (“end of main street green”) is reached.

Study Approach 1. Develop a simple sample problem involving a 3 signal coordinated arterial with typical peak hour traffic volumes, typical intersection lane configurations, and typical signal phasing. 2. Develop two reasonable coordinated timing plans with different cycle lengths and offsets for this 3-signal system. (A 120 second “before” plan and a 180 second “after” plan were developed.) 3. Establish a 20 minute study period beginning at 4:40 PM and ending at 5:00 PM. Set the change-point from the before plan to the after plan at 4:45 PM.

Study Approach (Con’t.) 4. Using Hardware-in-the-Loop (HIL) simulation, run the sample problem with dwell, percent forward, and short way offset seeking at various traffic volume levels. Obtain delay info. from CORSIM for each 20 minute run. 5. Run the sample problem using only CORSIM (no HIL) with one cycle, two cycle, and three cycle offset seeking at various traffic volume levels. Obtain delay info. from CORSIM for each 20 minute run. 6. To establish a baseline, run the sample problem using just the 120 sec. plan and then run it again using just the 180 sec. plan. Obtain delay info. from CORSIM for each 20 minute run and combine delay results using a weighted average based on the time each of the 2 cycle lengths is in effect during a transitioning run.

Study Approach (Con’t.) 7. Make various delay comparisons: a.) Between baseline condition and the 3 different controller transitioning modes b.) Between baseline condition and the 3 different CORSIM transitioning modes 8. Identify which controller transitioning method performs best at different volume levels and determine which CORSIM transitioning method most closely corresponds to real-world transitioning (if any).

Equipment Set-Up 3 CID’s 3 Controller’s

… and One Computer Running CORSIM Go Gators !

TRAFVU Screen for 3 Signal System

TRAFVU Screen for Typical Intersection

CORSIM Timing Screen This will cause transitioning problems

Potential CID Success Story Discovery of a previously undiagnosed controller problem Problematic behavior was observed during dwell and percent forward transitioning, with total transition times of over 15 minutes! This problem was later confirmed with the manufacturer and they are currently working on a solution.

VERY PRELIMINARY RESULTS: 1.CORSIM and HIL Simulation don’t seem to be producing the same delay results with the same controller settings. 2.For some unknown reason, CORSIM produces the same delay results regardless of which form of transitioning is chosen (Immediate, 2 cycle, or 3 cycle) 3.At low to moderate traffic volumes, HIL simulation suggests that dwell and percent forward transitioning cause less of an increase in delay than short way transitioning.

Discussion …

End of Presentation …  Thank you