Telecommunication facilities, in particular the numbers of main telephone lines in the world have listed a very even and balanced development since the very beginning. For 56 nations with the highest number of main telephone lines the author provides the review of respective capacities, distribution per l OO inhabitants, and respective growth rate with the average annual growth rate in the period between 1987 and 1988. Economic comparison bas been drawn to the gross national product and respective correlation function bas been provided of the distribution of main lines per 100 inhabitants and gross national product per capita. The countries covered in this review account for over 97% of world telephone communication capacities.

As a result of an extensive research, different models of review and follow-up/monitoring of transport demand and freight flows have been obtained. Transport demand is either related either to the origin or destination while freight flows may be incoming and outgoing (inward and outward-bound) in (to) a given location or facility, as for instance a container terminal. Furthermore, simulation and mathematical models of monitoring and review of distribution channels and transport flows optimization have been dealt with in this paper.

This paper deals with the proposed model for determining the optimal number of parking places following the conditions and requirements of high standard of provision of services to the users and positive economic effects of car parking operations. The characteristics of car parking operations have been obtained through simulation on the model by varying the input parameters as the intensity of the input flow, parking times, number of parking places, etc. Checking of the results obtained has been completed by application of economic methods.

This paper deals with the drugs which affect the psychophysical characteristic of man, commonly known as trigonic drugs. In the spirit of our regulations trigonic fall into the category of those drugs ultimately prohibited to motorists and machine operators and the category of those drugs known for possible effects upon the psychophysical characteristics of a motorist. It has been suggested to the motorists to study carefully respective instructions for use i.e. administration of these drugs and get familiar with the effects and side-effects of the medicine. Trigonics have been indicated to account for some 12% of all road traffic accidents reported causes.

Piggy-back transport has been up to this point of time the most efficient segment of freight transport by means of modern technologies combining rail and road aspects. This modern transport mode as compared to traditional transport offers a variety of advantages in the shape of: economical consumption of petroleum products, higher rail and road fleet utilization coefficient, longer road vehicle(s) operation life, reduced wear of carriageways, higher-quality and safer transportation, reduced transportation costs, environmental concerns, etc. In our country in 1981 and 1982 respectively a piggy-back train was 6perating on the Jesenice- Ljubljana and Zagreb-Belgrade-Gevgelia routes to be cancelled subsequently: such a train is presently operating only on the Jesenice-Ljubljana- Koper route. In the light of the above listed advantages it will absolutely be necessary to re-introduce this train on the one-time routes, as well as on the Zagreb-Rijeka and ZagrebSplit and Zagreb-Osijek- Vinkovci routes. Measures on the prevention of adverse environmental effects of traffic and legislative, management, engineering and technological, educational and other effects {as dealt with in this paper) should necessarily be updated, modernized and intensified in their implementation. This will yield the expected and aspired-to effects of environmental protection and advanced traffic safety.

Traffic infrastructure as an inseparable segment of community and business life takes an important position in the sphere of a harmonious development of all segments of the social reproduction process. This means that a harmonious development in the area of a rational and economic investment activity including traffic infrastructure facilities must inevitably take heed of the effects of the external economy and external diseconomy. In this the traffic infrastructure facilities develop into the elements of harmonious relationships in the process of the investment activity, which must not and absolutely cannot be unilateral. The complex aspect of viewing both positive and negative effects is a distinctive quality of each and every rational investment activity, because it is an accepted fact that there exists no such activity which yields only positive effects. These investment activities oriented towards traffic infrastructure facilities in the community and business systems must arise from more complex reviews and verified methods for the final effects to incorporate all the elements of a harmonious relationship of positive and negative effects of a concrete investment operation. The paper deals with respective effects and indispensable coordination of external economy and external diseconomy, which has been regarded in the up-to-date processes of the investment activity as only a marginal problem, present yet not worth deeper reviewing. .By gradual dehumanization of the environment coming as a result of an uneconomical and inadequately controlled investment activity i.e. advance exploitation of the resources of future generations, we face a problem which no longer has a restricted effect but has already metastasized into all cells of life and has been faking daily its gigantic toll.