By determining the level crossing as a system and structuring the model for forecasting events an attempt has been made to find the optimum levels of securing level crossings. The assessment of the respective level of safety, behavior of road users, local conditions and impact of stochastic regularity with input and output values being determined in an exact manner, a prerequisite has been created for the elaboration of a systematic system analysis. The incidence of emergencies, stopping and waiting times of motor vehicles, utilization C()sts and number and stopping and waiting times of trains have been forecast by mathematical methods and computed by way models. The elaborated algorithm for selection of the optimum level of safety of level crossings creates the possibilities for obtaining reliable elements for decision making in transition from the existing to a newly introduced safety aspect.

The paper deals with current issues of Zagreb suburban traffic. A number of problems have been identified: obsolete infrastructure facilities, congested traffic routes, deficiency of transportation means and low level of transportation service. All this reflects upon energy and space utilization, deterioration of environmental balance, increased noise pollution, stress situations and inconveniences a person, i.e. a passenger experiences in traffic. The author discusses the need for radical changes in suburban traffic planning. These changes are seen in the introduction of railways becoming a major aspect of suburban transport, because the railways can provide transport of large numbers of passengers in short periods of time, while the identified negative aspects are being eliminated or reduced to the minimum. It is therefore necessary to conceive the new system of suburban transport. This could be materialized through the elaboration of the projects of complete suburban transport segment. This in the first place refers to the infrastructure contents as by-pass lines, Medvednica Tunnel, Samobor line, airport links, passenger terminals, stations with platforms at an elevation parallel with the floor of the cars and special train cars for mass transport of passengers with broad seiding doors for quick getting of and off the trains. This projects can be elaborated by and expert and specialist team organized a in a research institution to be assigned the task from the very beginning- i.e. from the

In the light of the fact that the traffic system of the Republic of Croatia makes part of the European and world traffic system and that the geographical location of Croatia creates major comparative advantages for the nation as a maritime, Mediteranean and Danube-basin country to develop traffic for its own needs and of other countries - the role of river transport becomes evident. The river transport in the Republic of Croatia offers major possibilities for serving the industry and businesses in freight transport in domestic and international traffic. The river navigation routes in Croatia lie in economically most developed regions. The nation's potentials in utilization of river navigation are rather pronounced, and if we keep in mind that this makes one of the least expensive aspects of transport its advantages become clearly manifest. In parallel with promoting river navigation on the Danube as planned in cooperation with Europe, the traffic policy should become an instrument of influence in promoting river navigation on the Sava and the Drava as important Danube tributaries, with supporting the development of the river fleet of vessels in conformance with the requirements of respective transport demand forecasts. Particular attention should be assigned to the development of the existing and building of new river ports in particular on the Sava River, in the first place in Zagreb, Jasenova, Samac and Zupanja. For reasons of quality and technology aspected justified and sound option of better linkage of the Adriatic and the Danube-basin region i.e. of Croatia and the Central European countries, it is indispensable to build the port of Zagreb (as the most rational/ink of the Adriatic and the Danubebasin region) and initiate the construction of the Samac-Vukovar Canal as a direct fluvial exit of Croatia in to Europe and beyond.

The paper deals with a segment of research examining the possibility of application of the theory of recognizing samples as the core of a diagnosing model. System diagnosing is based upon the signals of operation process. Diagnosing rules are determined based upon the sample of diagnosing signals produced by different simulated aspects of system technical condition. The model has been verified in the process of Diesel engine fuel injection system diagnosing. The fuel injection pressure signal in front of the injector has been used as a diagnosing signal.

The paper discusses the results of the survey mounted in Zagreb in the summer of 1991 dealing with the perception of urban traffic by senior citizens. The survey involved 192 respondents, citizens of 55 years of age and above (traffic-related age criterion) and it served for obtaining the attitudes and opinions of senior citizens regarding some basic traffic problems of the Zagreb metropolitan area: assessment of public transport, urban traffic concept, and respective availability/ ease of access. Particular interest has been paid to the relationship of responses and respondents' characteristics (sex and 'mobility').

The paper deals with a theoretical analysis of the problem of non-uniform defining of a group of non-conventional transport technologies. In this some basic approaches have been differentiated of various defining criteria, engineering/ technological and legal. In a comparative analysis of specific systems of air transport the author deals with the assessment of the possibilities for the utilization of vehicles of this transport aspect in nonconventional transport technologies. The author discusses the prerequisites of application and development of non-conventional transport technologies with air routes incorporated into the transport chain.

Timely delivery of material and equipment to the site at minimum costs and minimum risk makes one of the major elements in successful construction trade. Cutting down the time of equipment being ready for transport and the time of being actually delved on to the construction site can be attained through good preparations and sensible management. Transport program makes part of the complex process of construction of buildings connecting the manufacturing and construction program by making optimum use of the available time to grant timely flow of materials and equipment to the construction site at intervals and in quantities as defined in the construction/erection program. Experience shows that the preparation of a transportation program should be initiated as early as the time of the elaboration of the preliminary design. Being its integral part, the transport study considers in a professional and sensible way the usability of access lanes to the site, available transportation  leans, development of the network of traffic links, construct of new ports, etc. The study gives an advance insight to concerned parties into the conditions of transport and conditions to be met by equipment for transport thus making possible timely preparation and management. By promoting successful transport it certainly adds to successful construction activities.