Dynamic routing

Unforeseen events may occur during the execution of planned routing. These include unexpected traffic congestion, vehicle breakdown, blocked roads, and new customer orders. These events may cause disruptions in the scheduled routes and services of customers, and must be addressed appropriately. Dynamic routing facilitates incorporation of add and drop stops as needed, adjustments to traffic and weather conditions, and minimizing operating costs. 

Dynamic routing can be implemented in multiple ways local updates, re-optimization, and advanced approaches. Local updating is usually limited to a simple insertion of new requests. Re-optimization involves solving the entire routing problem that may change the sequence of pick-ups and deliveries to customers. 

Clarke and Wright (1964) designed a heuristic, known as the savings heuristics, for dynamically creating tours that often lead to shortest total distance traveled. It begins by assuming that one vehicle travels from the depot directly to a node and returns to the depot (shown as double headed arrows). As an example (adapted from Couriel (2011)), consider the initial tours (with solid lines), shown in the Fig. 5.10. The dashed lines show paths that may be used but are not in use currently. 

In Fig. 5.11, by linking nodes 2 and 3, a tour can be created for a single vehicle to cover nodes 1,2,3,1 in that sequence. By linking nodes 2 and 3, we add 7 miles (the 

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Dynamic routing Planning out the stops in advance is not always possible. Often all stops aren t known until the vehicles are in the field, partway into their routes, forcing them to double back or circulate to finish their tour. In addition, travel times and costs are time dependent because vehicles confront the commuter rush hours on the road, as well as at the loading and receiving docks. 

Fread, D.L. (1973). Effects of time step size in implicit dynamic routing. Water Resources Bulletin 9(2)-. 338-351. 

Cheung B, Choy K, Li C, Shi W, Tang J (2008) Dynamic routing model and solution methods for... 

A dynamic route to structure and fimction Recent advances in imine-based organic nanostructured materials 13 C9. 

Thoma, Y Sanchez, E Arostegui, J. M. Tempesti, G. (2003), A dynamic routing algorithm for a bio-inspired reconfigurable circuit. Lecture notes in computer science. 

Nikaein, N., Laboid, H., and Bonnet, C., Distributed Dynamic Routing Algorithm (DDR) for Mobile Ad Hoc Networks, Proceedings of the MobiHOC 2000 First Annual Workshop on Mobile Ad Hoc Networking and Computing, 2000. 

With limited redundancy, highly dynamic routes, and strictly remote supervision, small UAS face formidable automation challenges. As the number of unmanned aircraft increases and as safety-oriented technology development continues to lag behind the development of new platforms, mission capabilities, and operational effi-ciency (e.g., one operator for multiple vehicles), it is beconung increasingly urgent that these issues be addressed. In addition, a large user base... 

FIGURE 8.12 Example of a dynamic route information panel (DRIP) in the Netherlands. (Adapted from Verkeer.wikia.com, http //verkeer.wikia.com/wiki/Verkeersmonitoring voor Dynamisch Verkeersmanagement.)... 

Janssen. W.H. and Martens, M.H. 1997. Het combineren van DRIPS met andersoortige infor-matiedragers een evaluatie in de rijsimulator [Combining dynamic route information panels (DRIPs) with other information bearers An evaluation in the driving simulator]. 

Martens, M.H. and Janssen, W.H. 1999. Grafische informatie op dynamische route informa-tie Panelen een rijsimulatorstudie [Graphic information on dynamic route information panels A simulator study (in Dutch)]. Report TNO-TM-C024. TNO Soesterberg, the Netherlands. 

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