90 likes | 206 Views
Determination of Number of Probe Vehicles Required for Reliable Travel Time Measurement in Urban Network. Determining the Number of Probe Vehicles for Freeway Travel Time Estimation by Microscopic Simulation. Conclusions.
E N D
Determination of Number of Probe Vehicles Required for Reliable Travel Time Measurement in Urban Network
Determining the Number of Probe Vehicles for Freeway Travel Time Estimation by Microscopic Simulation
Conclusions • the minimum number of probe vehicles necessary is determined by the type of travel time distribution. • the variance of the distribution would affect the minimum number of probe vehicles needed despite the type of distribution. • the stability of the distribution would also affect the minimum number of probe vehicles necessary.
Factors Affecting Minimum Number of Probes Required for Reliable Estimation of Travel Time
Ideas • Optimize the combination of # of vehicles and sensor spacing • Independent variables: • # of probes • Sensor spacing • Dependent variables: “Error” • How to define “Error”? (variance) • How to relate “Error” to # of probes and Sensor spacing?
Information • Information from probe: • For each probe i, Vi, xi, at any instantaneous time t0 • For each probe i, Tti in time period t0-t1 • Information from detector: • Vt (time mean speed) in the previous short time period t0-t1 • Occ. and Flow • Spacing
Objectives • Online travel time prediction • Offline travel time estimation Data • Simulation • Trajectory