ML032510724
| ML032510724 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 05/31/2003 |
| From: | KLD Associates |
| To: | Entergy Nuclear Northeast, NRC/FSME |
| References | |
| NL-03-139 KLD TR-369 | |
| Download: ML032510724 (6) | |
Text
APPENDIX CTraffic Simulation Model: PCDYNEV Indian Point Energy CenterC-1KLD Associates, Inc.Evacuation Time EstimateRev. 1APPENDIX C: TRAFFIC SIMULATION MODEL: PCDYNEVA model, named PCDYNEV, is an adaptation of the TRAFLO Level II simulation model, developedby KLD for the Federal Highway Administration (FHWA), with extensions in scope to accommodate all types of facilities. This model produces an extensive set of output Measures of Effectiveness (MOE) as shown in Table C-1.The traffic stream is described internally in the form of statistical flow histograms. These histogramsdescribe the platoon structure of the traffic stream on each network link. The simulation logic identifies five types of histograms: The ENTRY histogram which describes the platoon flow at the upstream end of thesubject link. This histogram is simply an aggregation of the appropriate OUTPUT turn-movement-specific histograms of all feeder links. The INPUT histograms which describe the platoon flow pattern arriving at the stopline. These are obtained by first disaggregating the ENTRY histogram into turn-movement-specific component ENTRY histograms. Each such component is modified to account for the platoon dispersion which results as traffic traverses the link. The resulting INPUT histograms reflect the specified turn percentages for the
subject link. The SERVICE histogram which describe the service rates for each turn movement. These service rates reflect the type of control device servicing traffic on this approach; if it is a signal, then this histogram reflects the specified movement-specific signal phasing. A separate model estimates service rates for each turn movement, given that the control is GO.Table C-1. Measures of Effectiveness Output by PCDYNEVMeasureUnitsTravelVehicle-Miles and Vehicle-TripsMoving TimeVehicle-Minutes Delay TimeVehicle-Minutes Total Travel TimeVehicle-Minutes Efficiency: Moving Time/
Total Travel TimePercent Indian Point Energy CenterC-2KLD Associates, Inc.Evacuation Time EstimateRev. 1Mean Travel Time per VehicleSecondsMean Delay per VehicleSeconds Mean Delay per Vehicle-MileSeconds/Mile Mean SpeedMiles/Hour Mean OccupancyVehicles Mean SaturationPercent Vehicle StopsPercentThese data are provided for each network link and are also aggregated over the entire network. The QUEUE histogram that describe the time-varying ebb and growth of the queueformation at the stop line. These histograms are derived from the interaction of the respective IN histograms with the SERVICE histograms. The OUT histograms that describe the pattern of traffic discharging from the subjectlink. Each of the IN histograms is transformed into an OUT histogram by the control applied to the subject link. Each of these OUT histograms is added into the (aggregate) ENTRY histogram of its receiving link.Note that this approach provides the model with the ability to identify the characteristics of each turn-movement-specific component of the traffic stream. Each component is serviced at a different saturation flow rate as is the case in the real world. Furthermore, the logic recognizes when one component of the traffic flow is encountering saturation conditions even
if the others are not.Algorithms provide estimates of delay and stops reflecting the interaction of the IN histograms withthe SERVICE histograms. The logic also provides for properly treating spillback conditions reflecting queues extending from one link into its upstream feeder links.A valuable feature is the ability to internally generate functions that relate mean speed to density oneach link, given user-specified estimates of free-flow speed and saturation service rates for each link.
Such relationships are essential in order to simulate traffic operations on freeways and rural roads, where the signal control does not exist or where its effect is not the dominant factor in impeding traffic flow.All traffic simulation models are data-intensive. Table C-2 outlines the input data elements. This input describes:
Indian Point Energy CenterC-3KLD Associates, Inc.Evacuation Time EstimateRev. 1 Topology of the roadway system Geometrics of each roadway component Channelization of traffic on each roadway component Motorist behavior that, in aggregate, determines the operational performance ofvehicles in the system Specification of the traffic control devices and their operational characteristics Traffic volumes entering and leaving the roadway system Traffic composition.To provide an efficient framework for defining these specifications, the physical environment isrepresented as a network. The unidirectional links of the network generally represent roadway components: either urban streets or freeway segments. The nodes of the network generally represent urban intersections or points along the freeway where a geometric property changes (e.g. a lane drop, change in grade or ramp).Figure C-1 is an example of a small network representation. The freeway is defined by the sequenceof links, (20,21), (21,22), (22,23). Links (8001, 19) and (3, 8011) are Entry and Exit links, respectively. An arterial extends from node 3 to node 19 and is partially subsumed within a grid network. Note that links (21,22) and (17,19) are grade-separated.
Indian Point Energy CenterC-4KLD Associates, Inc.Evacuation Time EstimateRev. 1Table C-2. Input Requirements for the PCDYNEV ModelGEOMETRICS Links defined by upstream downstream node numbers Links lengths Number of lanes (up to 6) Turn pockets Grade Network topology defined in terms of target nodes for each receiving linkTRAFFIC VOLUMES On all entry links and sink/source nodes stratified by vehicle type: auto, car pool, bus, truck Link-specific turn movements or O-D matrix (Trip Table)TRAFFIC CONTROL SPECIFICATIONS Traffic signals: link-specific, turn movement specific Control may be fixed-time or traffic-actuated Stop and Yield signs Right-turn-on-red (RTOR) Route diversion specifications Turn restrictions Lane control (i.e. lane closure)DRIVER'S AND OPERATIONS CHARACTERISTICS Drivers (vehicle-specific) response mechanisms: free-flow speed, aggressiveness,discharge headway Link-specific mean speed for free-flowing (unimpeded) traffic Vehicle-type operational characteristics: acceleration, deceleration Such factors as bus route designation, bus station location, dwell time, headway, etc.
Indian Point Energy CenterC-5KLD Associates, Inc.Evacuation Time EstimateRev. 1 8001 8011 3 6 9 12 14 15 16 19 17 2 8107 8 8012 13 22 8009 8010 8005 23 8003 8104 5 10 11 8014 25 24 21 8008 8007 8006 8004 8024 20 8002Entry, Exit Nodes arenumbered 8xxxFigure C-1: Representative Analysis Network