SISTA. Sven Maerivoet.

Transcription

1 SISTA Sven Maerivoet Katholieke Universiteit Leuven Department of Electrical Engineering ESAT-SCD (SISTA) May, 26th 2004 SYSTeMS Seminar SISTA (26/05/2004) 1

2 Short overview Microscopic traffic flow models Traffic Cellular Automata + CATSIM Analysis of traffic measurements Project Sustainability Effects of TMS Earlier: Federale Diensten voor Wetenschappelijke, Technische en Culturele aangelegenheden (DWTC) Now: Federal Science Policy SYSTeMS Seminar SISTA (26/05/2004) 2

3 Microscopic traffic flow models SYSTeMS Seminar SISTA (26/05/2004) 3

4 Models of traffic flows Macro-/mesoscopic models Based on partial differential equations. Fluid dynamical models consider a traffic flow as a compressible fluid (i.e., continuum models); macroscopic. Gas kinetic models consider a traffic flow as a manyparticle system; mesoscopic. Microscopic models Consider each vehicle separately. (Too) many parameters and computationally intensive. SYSTeMS Seminar SISTA (26/05/2004) 4

5 Microscopic traffic flow models Bottom up approach: model vehicle dynamics. Car-following and lane-changing submodels. follower leader(s) (n) (n 1) space gap a (t + τ) ~ f(t,θ) n reaction time space-/time gap, agression, (relative) speeds, SYSTeMS Seminar SISTA (26/05/2004) 5

6 Traffic Cellular Automata + space (lattice of cells with Δx = 7.5 m) t t+1s upstream v = 0 downstream Δx Δt v = 3 v = 1 x(t + 1) = x(t) + v(t) time v = 1 v = 1 Car-following submodel = collection of local rules SYSTeMS Seminar SISTA (26/05/2004) 6

7 Example: VDR-TCA (Barlović) Consider a unidirectional, circular road with one lane: space breakdown vehicles shock wave time SYSTeMS Seminar SISTA (26/05/2004) 7

8 Other TCA models space space CA-184 VDR-TCA time time space space STCA TOCA time time SYSTeMS Seminar SISTA (26/05/2004) 8

9 Simulation of a large scale network Flanders has approximately 1350 km of highways: 540,000 cells (7.5 m/cell; 3 lanes/direction) Goal: reasonably detailed and very fast simulation. SYSTeMS Seminar SISTA (26/05/2004) 9

10 CATSIM Distribute the highways over several computing units: Antwerp computer farm Ghent E17 E19 E17 E40 master E40 Brussels E19 parallellisation through distributed computing (Java) SYSTeMS Seminar SISTA (26/05/2004) 10

11 Analysis of traffic measurements SYSTeMS Seminar SISTA (26/05/2004) 11

12 Analysis of traffic measurements Flemish highway road network: ± 1655 sensors 10 6 measurements/year 3.24 GB Single loop detectors / Cameras (Traficon) SYSTeMS Seminar SISTA (26/05/2004) 12

13 What is being measured? After each minute, the following quantities are aggregated: Number of cars Number of trucks Occupancy Average speed SYSTeMS Seminar SISTA (26/05/2004) 13

14 Remember all those mondays in 2001? vacation period SYSTeMS Seminar SISTA (26/05/2004) 14

15 Quality problems Not necessarily zero! SYSTeMS Seminar SISTA (26/05/2004) 15

16 Time-space correlations (one week) SYSTeMS Seminar SISTA (26/05/2004) 16

17 Sustainability Effects of Traffic Management Systems SYSTeMS Seminar SISTA (26/05/2004) 17

18 DWTC-CP/40 ( ) Katholieke Universiteit Leuven Department of Electrical Engineering SCD (SISTA) B. De Moor Department of Civil Engineering Traffic and Infrastructure B. Immers Centre for Economic Studies Energy, Transport, and Environment S. Proost Université Catholique de Louvain Centre for Systems Engineering and Applied Mathematics CESAME G. Campion / G. Bastin Universiteit Gent Electrical Energy, Systems, and Automation SYSTeMS R. Boel SYSTeMS Seminar SISTA (26/05/2004) 18

19 Sustainability Effects of TMS Traffic is dynamic in nature Demand Supply (travellers/traffic streams) (road infrastructure) Optimise traffic using the existing road infrastructure! Methods for optimisation? Optimisation criterion? adaptive control strategies (e.g., model predictive control) sustainable cost function SYSTeMS Seminar SISTA (26/05/2004) 19

20 A sustainable cost function (SCF) Characterise the concept of sustainability, e.g., SCF = emissions (air, noise) + incident risks + travel times environment supply personal Important: the SCF involves a trade-off! environment friendly capacity throughput SYSTeMS Seminar SISTA (26/05/2004) 20