The Diffusion of Transportation Effects In an Urban Network

Large urban centers are served by transport networks which consist of a great number of links and nodes. Predicting what the effects of the construction of a proposed link, the abandonment of superfluous elements, or the improvement of existing links will be on the traffic flows over the entire system is currently a timeconsuming and expensive undertaking. It is nevertheless, a necessary step investment appraisal. It is for proper often the case that the amount of available capital will only allow for the completion of a relatively small scale projects. The cost of a full traffic study to assess the impact of several competing proposals is the same no matter the size of the investments. It is often held that the high cost of a full traffic study as a percentage of the cost of a small road investment does not warrant the execution of one. The decision-making process would be better assured of success if a traffic study existed to fully illuminate the unique changes which are induced by each individual proposed link improvement. Any method which would reduce the cost of the study is therefore potentially valuable.