FULLY INTEGRATED CONTROL DESIGN:
FUTURE CONCEPTS

Deliverable Type: P

Contract Date: 31-03-95

Submission Date:31-03-95

Partners: TRUTh, TUC, INRETS, TRL, CMSU, SRILOG, RWS-DVK
Assoc. Partners: Ville de Paris, RWS-NH, SRC

1. INTRODUCTION

1.1 DRIVE II Context
1.2 Structure of the Report

2. AN INTEGRATED CONTROL APPROACH FOR TRAFFIC CORRIDORS

2.1 Introduction
2.2 Optimal Control Problem Formulation

3. A LINEAR PROGRAMMING APPROACH TO LARGE-SCALE LINEAR OPTIMAL CONTROL PROBLEMS

3.1 Introduction
3.2 Basic Approach
3.3 Results

4. AN INTEGRATED CONTROL APPROACH FOR TRAFFIC CORRIDORS: APPLICATION TO THE CORRIDOR PERIPHERIQUE OF PARIS

4.1 Network Description
4.2 Control Software Architecture
4.3 Results

5. INVESTIGATIONS OF INTEGRATED CORRIDOR CONTROL FOR THE M8 EASTBOUND IN GLASGOW

5.1 Description of test site
5.2 Control Strategies
5.3 Traffic data
5.4 Simulation tests
5.5 Conclusions

APPENDIX A: AN INTEGRATED CONTROL APPROACH FOR TRAFFIC CORRIDORS

APPENDIX B: A LINEAR PROGRAMMING APPROACH TO LARGE-SCALE LINEAR OPTIMAL CONTROL PROBLEMS

APPENDIX C: AN INTEGRATED CONTROL APPROACH FOR TRAFFIC CORRIDORS:APPLICATION TO THE CORRIDOR PERIPHERIQUE OF PARIS

APPENDIX D: INVESTIGATIONS OF INTEGRATED CORRIDOR CONTROL FOR THE M8 EASTBOUND IN GLASGOW

The developments reported in this Deliverable may be structured into four parts.

Part A presents a unified approach to the design of integrated control strategies for traffic corridors of arbitrary topology including both motorways and signal-controlled urban roads. The presented approach is based on suitable application of the store-and-forward modelling philosophy that leads to the formulation of a linear optimal-control problem involving a number of possible control actions, such as ramp metering, signal control, motorway-to-motorway control, route guidance, and VMS control. The control objective is minimization of a common criterion, such as the total delay or the total time spent in the network. The formulated optimal control problem may be resolved in real time using suitable algorithms to provide traffic-responsive queue management, particularly under saturated traffic conditions.

Part B presents a general algorithm for numerical solution of the problem formulated in part A. More precisely, part B considers the solution of large-scale linear optimal control problems subject to linear control and state constraints by application of a linear programming (LP-) based methodology. If a solution exists, the suggested algorithm allows its exact computation in a finite number of iterations. The algorithm is based on a particular LP-method that is suitably modified and adapted to the structure of the considered discrete-time dynamic problem in order to keep the computation time low and efficiently store the arising large, but sparse, matrices. The efficiency of the approach is demonstrated via a practical example arising in the field of traffic control in data-communication networks. The algorithm is shown to solve problems involving several thousands of variables in few CPU-s on a workstation, thus enabling real-time optimal control for a number of potential practical applications including integrated corridor traffic control.

Part C describes an application of the optimal control problem formulation of part A and of the numerical solution algorithm of part B to a medium-size network from the Corridor Pé riphé rique in Paris. In fact, an overall computer code based on parts A and B has been produced that allows integrated optimal control of corridor networks with arbitrary configuration. The integrated control problem is solved for the Corridor Pé riphé rique subnetwork using a realistic demand load for several cases including:

The optimal results obtained from the optimization procedure are used as inputs to the macroscopic simulation tool METACOR, developed and validated within EUROCOR, in order to test their relevance and efficiency in a realistic simulation environment.