ML063460318
| ML063460318 | |
| Person / Time | |
|---|---|
| Site: | Indian Point  |
| Issue date: | 12/08/2006 |
| From: | KLD Associates |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| FOIA/PA-2006-0299 | |
| Download: ML063460318 (6) | |
Text
F.F- --f° .APPENDIX C Traffic Simulation Model: PCDYNEV/2k APPENDIX C: TRAFFIC SIMULATION MODEL: PCDYNEV A model, named PCDYNEV, is an adaptation of the TRAFLO Level II simulation model, developed by 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 histograms describe the platoon structure of the traffic stream on each network link. The simulation logic identifies five types of histograms:
0 The ENTRY histogram which describes the platoon flow at the upstream end of the subject 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 stop line. 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 PCDYNEV Measure Units Travel Vehicle-Miles and Vehicle-Trips Moving Time Vehicle-Minutes Delay Time Vehicle-Minutes Total Travel Time Vehicle-Minutes Efficiency:
Moving Time/Total Travel Time Percent Indian Point Enerav Center C-1 KLD Associates.
Inc.Evacuation Time Estimate I Rev. I Mean Travel Time per Vehicle Mean Delay per Vehicle Mean Delay per Vehicle-Mile Mean Speed Mean Occupancy Mean Saturation Vehicle Stops Seconds Seconds Seconds/Mile Miles/Hour Vehicles Percent Percent These 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 queue formation 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 subject link. 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 with the 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 on each 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 Center Evacuation Time Estimate C-2 KLD Associates, Inc.Rev. I f
- 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 of vehicles in the system* Specification of the traffic control devices and their operational characteristics
- Traffic volumes entering and leaving the roadway system 0 Traffic composition.
To provide an efficient framework for defining these specifications, the physical environment is represented 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-I is an example of a small network representation.
The freeway is defined by the sequence of 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 Center C-3 KLD Associates, Inc.Evacuation Time Estimate Rev. I Table C-2. Input Requirements for the PCDYNEV Model GEOMETRICS
- 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 link TRAFFIC VOLUMES* On all entry links and sink/source nodes stratified by vehicle type: auto, car pool, bus, truck 0 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 Center Evacuation Time Estimate C-4 KLD Associates, Inc.Rev. I Entry, Exit Nodes are numbered 8xxx Figure C-1: Representative Analysis Network Indian Point Energy Center Evacuation Time Estimate C-5 KLD Associates, Inc.Rev. I