The presented material on the informatization of the railways operation process discusses its requirement (or necessity) of defining logical technical and technological whose lending themselves to informization. Besides, the suggested proposal is aimed at the resolution of the basic issues of management and control of a company by precisely delineating or separating the operational from the tactical and strategic management and administration. A special review is dedicated to the information science aspect end completion of timetables. In the proposal of the subject solution a re-assignment has been completed of the existing institution of the department in charge of time-tables which in addition to the annual operation schedules have to issue daily schedules thus relieving the work load of the operational (executive) department, precisely defining the work plans for the work period, i.e. work situations. The proposed approach to the informatization is an unavoidable requirement i.e. prerequisite for the integration Jo the railways into the European demand and trends of future development and advancement improvement of operations.

Increased cares for clean environment and limited sources of energy have inevitably resulted in many laws to be passed. This paper deals with some important aspects of subjects laws treating motor exhaust fuzzes and fuel consumption. The expected effects of these laws as well as possible development trends in designing motor vehicles and their engines have been presented.

Digitalization of telecommunications systems is currently in progress. In the light of the fact that the transmission systems make one of the fundamental parts of the system, their capacities are important. This year a new generation of digital transmission systems with up to this point of time the highest rate of 2,5 Hb it/sec has been introduces. The paper discusses the features and possibilities of new systems and their integration into the strategy of telecommunications system digitalization.

The paper deals with the composition and quantities of waste tires of motor vehicles and possibilities of their utilization as possible potential secondary raw materials. The possible quantities available in the world, in the territory of former Yugoslavia, and the city of Zagreb have been reviewed. The possible available quantities of waste tires (pneumatics) in the year 1991 are as follows: in the world this comes to l. 7 x JO pieces of which 84% is still on automobiles, in former Yugoslavia it comes to 9.637.466 pieces or 267.049 tons, and in Zagreb it comes to 862.780 pieces or 18.635 tons while only as /itl/e as less than JO% is collected. It has been established that radial/ tires on automobiles on the roads of Croatia are used up on covered 50.000 kilometers of journey, 8,2% of radial-ply tn1ck tires after 60.000 kilometers 15% and cross-ply 17.1%. Out of a number of methods of utilization of waste rubber pneumatics the environmental and economic highest advantage rests in recycling and processing in cryogen procedure into rubber powder (recycler).

This paper deals with the emissions of carbon dioxide from motor vehicles as an important exhaust gas in the process of building up the greenhouse effect. The discussion covers al/levels of energy con versions -from the primary energy sources to the completion of useful transport by motor vehicles. In this different primary forms of energy are taken into account: appropriate conversion methods for obtaining the motor fuels, different types of fuels, and different structures of engines in the vehicles. The corresponding emissions of carbon monoxide is translated into the unit of transport output i.e. the coefficient is determined of the emission of carbon dioxide as a relevant indicator of the influence of individual elements in the entire chain of con versions in the emission of carbon dioxide.

This paper deals with the specific aspects of liner bus traffic reviewed based upon the information provided by the Main Zagreb Bus Station. A couple of recommendations have been given for the aspired-to improvement of transit passenger transport transit bus traffic and international transit traffic by methods of transport projections of volumes and flows.

The paper deals with the elements of ergonomics with reference to computer systems. The issue refers to the accommodation of working environment to the man i.e. the adjustment of conditions and equipment to the needs and requirements of workers. The analysis covers as follows: office furniture, equipment designing, lighting, noise level, temperature values, and humidity and office medical care information.

The paper deals with the system approach to the analysis of transport systems by means of models. The elaborated approach has been applied in the analysis by means of attend ant or service models or system often used as the only possible ones for studying designing and maintenance of transport processes at all levels.