True Adaptive Signal Control A Comparison of Alternatives Technical Paper #1154

Transcription

1 1 Smart Information for a Sustainable World True Adaptive Signal Control A Comparison of Alternatives Technical Paper #1154 Presentation to the 18 th World Congress on Intelligent Transport Systems Technical Session 95 (TS95) Wednesday 19 October Oct. 2011

2 Authors Cary Vick, PE Telvent Transportation (presenting) Farhad Pooran, PE, PhD - Telvent Transportation José Carlos Riveira Martinez - Telvent Trafico y Transporte 2

3 Purpose / Agenda Clarify definitions and capabilities of true adaptive signal control Urge selection of some type of advanced signal control We can do better with what we have It s not just for research any more Summarize approach of available technologies / products Not a comprehensive review and comparison of results 3

4 Deployment of Adaptive Signal Control Technologies RHODES ACSLite InSync SCATS SCOOT LA ATCS OPAC State with Pending ASCT State with Active ASCT 4

5 Categories of Signal Control Definitions (USDOT / FHWA Traffic Signal Control Handbook (Gordon and Tighe)): Isolated Time Based Coordination Interconnected Control Traffic Adjusted Control Traffic Responsive Control Traffic Adaptive Control The primary differentiator for Traffic Adaptive Control is the use of a traffic flow model to predict demand and adapt timings to meet expected traffic flows 5

6 What is NOT Adaptive Control Traffic Responsive: Trigger plan or timing changes Volume Density: Modify parameters based on demand Off-line Optimization: Real time measurements trigger re-optimization of timing plans Central + Local Optimization: Real time measurements trigger re-optimization of selected timing parameters (off set) then local control applies and adjusts All approaches have value, but they are NOT adaptive signal control 6

7 Summary of ASCT Alternatives Function ACS Lite InSync LA ATCS OPAC RHODE S Action P + R P + R P + R P + R P (only) Control System SCATS SCOOT UTOPIA ITACA NAZTEC QuicNet R (only) P + R Pro-active P + R R (only) R (only) Architecture Dist. Dist. Central Dist. Central Central Central Central Central Central Central Simulation Model? Yes Yes Yes Yes Yes No Yes Yes Yes No No Time Frame 5 10 min Phase/ Cycle / 15 min. Cycle Phase/ Cycle / 5 min. Sec by sec Cycle Cycle/ 5 min. 3 sec & Cycle 5 sec & Cycle 5 10 min 5 10 min Optimization S / O S / C / O / PS S / C / O S / C / O S S / C / O S / C / O / PS S / PS S / C / O / PS S / C / O S / C / O 7

8 Adaptive Traffic Signal Control Processes Offset Optimizer Split Optimizer Cycle Optimizer Traffic Engineer Offset Split Cycle weights weights weights Expert Rules Platoon modeling A or B A + B Occupancy Volume Intersection control B A 8

9 Operations of Adaptive Signal Control Traffic data at detection ponts Control Center Traffic Flow / Queue Model Intersection structure Operator / Traffic Engineer Real Time Data Mean travel time Queue lengths Exit flows Queue capacity Pro Active Timing Changes Street Observer for Calibration 9

10 Weighting Factors Apply Expert Rules to Adaptive Control Strategies ITACA Expert Rules System Usable range is -10 to +10 Positive weights apply importance to affected links Negative weights reduce importance of associated links 2 weighting parameters for each link (split and offset) 1 weighting parameter for each intersection (cycle) Can be adjusted in real time manually or by expert rules Each final weight may reflect adjustments by different sources Route A is highly Reduce weight for If Then Until congested Transversal Route B Intersection B20 has maximum queue 10

11 OPAC Hardware Configuration Advanced Traffic Controllers OPAC Single Board Computer (local) Upstream Advance Detectors Cabinet Traffic Signal Controller: Type 2070 or NEMA (TS1 / TS2) Stop Bar Detector Data Force offs & Holds Single Board Computer (Linux OS) running OPAC software 11

12 ACS-Lite Architecture ACS-Lite Computer Minimum 9600 baud Communications (serial or IP) NTCIP On-street Master (optional) Communications Interface and/or NTCIP Translators NTCIP controllers or Proprietary protocol controllers 12

13 Advantages of Predictive Modeling Continuous adjustment to changing demand Pro-active timing changes Optimal use of available capacity Adjusts to incident conditions The primary differentiator for Traffic Adaptive Control is the use of a traffic flow model to predict demand and adapt timings to meet expected traffic flows 13

14 Cycle Length Adaptability Incident Occurs 14

15 References: Stevanovic, Aleksandar, Adaptive Traffic Control Systems: Domestic and Foreign State of Practice NCHRP Synthesis 403, Transportation Research Board, Washington, DC, 2010 Gordon, Robert L, and Tighe, Warren Traffic Control Systems Handbook. Federal Highway Administration Report FHWA-HOP , Washington, DC, Gartner, N.H., F.J. Poorhan, and C.M. Andrews. Implementations and Field Testing of the OPAC Adaptive Control Strategy in RT-TRACS. TRB Paper No Presented at the 81st Annual Meeting of the Transportation Research Board, Washington, DC, Riveira Martínez, José Carlos. The Road to ITACA, internal white paper, Telvent, MacGowan, J., and I. J. Fullerton Development and testing of advanced control strategies in the urban traffic control system. Public Roads 43, no. 2, 3, and 4. 15

16 Smart Information for a Sustainable World Smart Information for a Sustainable World Thank You 19 Oct. 2011