The goods-traffic data collected by the Ministry of Transport about road, railway, in-land, waterways and pipe-lines give the metric tons and tonne-kilometers of transported goods within the national borders. These statistics under-estimate the transport activity because (i) they don't take into account the domestic coasting-trade and the international road-transports carried out by foreign transporters, (ii) they don't include in their definition the foreign part of international transport distances. By estimating all these traffics, the 1976 transport activity is increased by 13 per cent. Traffic explanation models must be qualified too. At last, (iii) the appraisal of the value of the traffic could give a better understanding to the goods-transport phenomena.
A traffic simulation model has been developed by IRT and ORION, in order to study the effectiveness of different traffic organization schema proposed by the maritime world for the English Channel since the grounding of Amoco Cadiz.After a short description of the basin principles of this model, as well as the shore based radar screen simulator issued from it, three criteria for safety evaluation (encounter situation, maneuver and maneuvering room) are developed.In the end an application to two schemes, the actual one, and a new one actually in discussion in IMCO, shows the main results obtainable by such a model.
It became common to quote energy consumption of transportation operations, generally expressed in g.o.e: by unit of service performed. The author, who does not deny the interest of such figures, to sensitive opinion of the necessary savings, wonders if they are useful as an element of decision. This usefulness seems insignificant to him for the operators. The unit-consumptions do not allow to obtain an accurate compared balance between two real operations. Furthermore, the criterion of the operators is only the total cost. As for the Authorities, they can think of bending theirs choices if the public cost of energy lies above its selling cost. It is the case of the imported energy and particularly of oil. In the field of transportation, this leads to cautious handling of the energetic comparisons between rail and road, for the energy consumed by the first is more and more of national origin.Even rectified about this fact, the unit-consumption cannot be used as elements of comparison between the operations. Each one requires the real of complex calculation of its energetic balance. Consequently, to influence the behaviour through reglementation, i.e. compendiously, does not allow to hope to reach the global economic optimum.The only logical way consists in representing on the cost of imported energy all the expanses it directly or indirectly involves what leads to the increases of certain market prices and sets hard social and political problems.Nevertheless, it is probably […]
The preparation and execution of transportation projects in Cairo involves the participa¬tion of several local and national agencies, each with its own perspectives on the problems and preferences among projects. Together this participation creates a "slate" of projects, a set of projects which by mutual agreement will be executed in the near future. This form of agreeing on project selection has significant strengths in that, for example, it produces a program which has the active support of all the agencies in the transportation sector. One the other hand, it means the detailed programming must be handled in a special way. In the absence of a central rationale for project selection, comparative evaluation between projects has a limited role, and implementation must always include several projects simultaneously to keep the interests of concerned agencies in balance. But one must remember: the slate is a plan, and for all its lack of scientific refinement, a robust, realistic plan.
This article exposes some opportunities of the segmentation method about urban travel behavior analysis. This method avoids analysis of a lot of contingency tables and helps to build a view of relationships between a phenomenon to be explained in a way to explain the aggregate mobility with some parameters making up a representation of the socio-economic context. The analysis allows to make out some large tendencies in travel factors but also shows the limits of this way of explanation by these socio-economic criterions. Search for more relevant elements requires to introduce other dimensions of the social reality.