capacity-constrained traffic assignment in network with residual queues and implementation in emme/2...
DESCRIPTION
Basic Assumptions for Assignment 1)Assignment for single time period (e.g. peak hour period); 2)Fixed O-D demands; 3)Fixed exit capacity for each link; 4)Vehicles in the residual queue, will follow the chosen route to reach destinations in the next period; 5)Link cost consists of travel delay cost and the residual queue delay cost; 6)Drivers always choose thre shortest routes 7)No spill back effect on travel times in upstream links.TRANSCRIPT
Capacity-constrained Traffic Assignment in Network with Residual Queues and
Implementation in EMME/2Yanping Zhang
Bucher, Willis & Ratliff Corp. 7920 Ward Pkwy, Kansas City, MO 64114
Tel.: 816-363-2696, Email: [email protected].: 816-363-2696, Email: [email protected]
16th International EMME/2 User’s Group Conference16th International EMME/2 User’s Group ConferenceAlbuquerque, New Mexico, Mar. 18-20, 2002Albuquerque, New Mexico, Mar. 18-20, 2002
Network with Residual Queues
• Residual Queues - Overcapacity flow• Residual queue delay• Link outflow <= Link exit capacity • Unbalanced O-D flow• Spill-back queues on upstream link
Basic Assumptions for Assignment
1) Assignment for single time period (e.g. peak hour period);
2) Fixed O-D demands; 3) Fixed exit capacity for each link;4) Vehicles in the residual queue, will follow the chosen
route to reach destinations in the next period;5) Link cost consists of travel delay cost and the residual
queue delay cost;6) Drivers always choose thre shortest routes7) No spill back effect on travel times in upstream links.
Simple Example
Comparison of Assignment Results
Assignment Model Formulation
User Equilibrium Assignment in Network with Queues
Solution Method
• Adding shadow links and modifying cost function
• Shadow links (only for carrying queues)
Path Operator in EMME/2
• Cut-off path operator (splitting the queue-delay path flow)
Equivalent Model in the Modified Network
Approximation of Link Cost Function
Solution Algorithm
Solution Algorithm
Example
Conclusion
• Model for assignment in network with Queues;• Solution method with modified network;• No consideration of queue spill-back • Extension to Multiple period Assignment.