Dear all,
I am conducting a research on optimising a regional road network problem. My goal is to find an optimal solution that can minimise total travel time from all starting nodes to all terminal nodes (i.e., OD-matrix) and minimize total length of newly added/planned links at the same time based on the theory of Scott (1970s). Namely, I hope to maximise connected links and minimize total number of newly added links.
I find some algorithms (short path algorithm and spanning tree algorithm) to calculate the accessibility indicators. I am right now a bit lost. As I can't access travel flow data to calculate the total cost of travel, I am not be able to conduct a linear programming study on this issue. I am right now a bit confused and lost, hope you can provide me with some pointers on how to move on with this research. Any advices and suggestions are highly appreciated.
Best,
Andrew
The way you have asked the question suggests that you have already begun to realize that this is a very difficult problem -- in some ways the core problem in regional economics and transport planning.
Suppose you have some existing small roads joining some places, but not necessarily optimized or planned. Which of these roads would be "upgraded" to form a network to serve the nodes. As you mention, a minimum weight spanning tree might result in the shortest overall length of network infrastructure, but some of the OD flows would have a very lengthy path. So short network may mean lengthy interactions.
Another problem is that the network may be built to reflect some economies of scale --- so a nice fat link can carry lots of flow more easily than a number of small ones. This idea of rewarding larger bulk movements might be something like what you need. We published a paper that designed a network with network economies of scale. (It is by Horner and O'Kelly you can see it on RG.)
Finally, your question is somewhat like the problem that faced planners of the US Interstate System --- they planned to make connections along established corridors, joined areas that were left without good connections, and overall provided a mesh of very high capacity links to join major cities for civilian and military needs. Look at some of the early work by MARBLE and GARRISON.
You will find that you have asked a classic question.
Here is the paper link
Article Embedding Economy of Scale Concepts for Hub Network Design
Dear Dr. O'Kelly,
Thank you for your sharing.
Yes, I have come across some interesting papers on the interstate highway system planning in US, and state highway in Texas. I noticed a lot of results concluded are hardly based on the concept of optimization.
My logic is simply like Scott's model that the increase of new links would lead to the decrease of OD travel time. At the same time, increase the total construction cost (if measured by link length). I assume that there must be an optimal point where the total construction cost are managed to be minimized while the total accessibility are increased.
Yes, your answer certainly offers me a new perspective to look at this issue. Yes, I initially tend to do an ex-post evaluation on the planned network from a regional development perspective. Somehow, I am stuck here. The hub-network approach might just fit in the context of a developing economy.
I will give more feedback after I finish the paper you shared. Your suggestions are highly appreciated.
Best,
Andrew
- Badges
- Science topic
- Similar topics
- Biological Science
- Bioecology
- Systems Ecology
- Landscape Ecology
- Connectivity