The access to a single vertex of the non-directional transportationnetwork graph can be defined in various ways, but ifwe want to classifY the vertices and at the same time avoid ambiguity,then each of them has to be assigned a certain number.The paper uses the method for detemzining the access to a singlevertex based on the description of the transportation networkusing the symmetrical matrix of incidence. By knowingthe matrix of incidence it is possible to detemzine the eigenvaluesi.e. eigenvectors, and their comparison detemzines the valuesfor single vertices. Apart from describing the method, theconcrete example of the tram network of the city of Zagreb hasbeen analysed. Based on the obtained analysis results, it is possibleto detemzine the efficiency of connecting single vertices inthe considered transportation network, i.e. to propose its improvements.

In view of the fact that there are different approaches tostudying traffic in states of emergency, this article discusses oneof the possible approaches to research of global standpoints inthe analysis and assessment of the factors of exposure, menace,level of risk and danger of traffic systems in states of emergency.

About 50% of the analyses of actual road traffic accidentsare the analyses of various collision conditions of vehicles, i.e.various collisions of two vehicles or crashes of vehicles intovarious types of solid barriers. Such analyses, however, requirethat the values of vehicle post-collision movement parametersof its kinematics are determined with as much accuracy as possible.Since methods commonly LLSed in the present forensic expertisedo not provide satisfactory results by not taking into accountall the elements of the vehicle movement, this paper presentsanalytic considerations of the issue, thus determining relativelysimple and for the practice acceptable analytical expressionswhich can be LLSed to detennine the vehicle movement parametersimmediately following collision.

Postal administration world-wide is improving the postaltraffic also by introducing modem automation throughout itsoperation in mail transport.The Croatian Post must also carry out this demanding andchallenging project which must necessarily be well planned andimplemented as soon as possible. The automation of the operatingprocedures in the technological phases of mail-piecestransmission provides a significant substitution for the slowand expensive manual work, resulting in substantial reductionof costs, rise in the quality level of services and cutting down ofthe time-limit control of transmission.This is the aim of this article, as preliminary communication,which is based on the carried out research regarding importanttraffic parameters in the post centre Zagreb, as the largestone in Croatia. The results can also be used as adequate referencefonn for the research in other post centres ofCroatia. Afterthese studies and the obtained relevant infonnation, amethod of designing new rationally organised postal network ofCroatia in all segments of mail-pieces transmission would follow,as well as fanning of a suitable postal code and developingof the Croatian postal code map. This comprehensive workpresents the preparation phase of the project and it is absolutelynecessary for the success of the general automation in the Croatianpostal traffic.

In radio network planning, the goal is to specify optimalbase station locations, service areas, antenna patterns and handoverstrategies for a given mobile radio system. The system performanceis fixed and the radio channel is subject to optimisation.Network planning requires channel characteristics thatprovide information about the expected sendee quality, especiallythe outage probability. The channel description must onlyperform as a qualitative measure of an actual receiving area.Power delay profiles are a convenient and very common descriptionof channel time dispersion, which can be easily physicallyunderstood as footprints of individual reflected or scatteredpaths, and provide a capability to a network planning engineerto discover areas of heavy time dispersion and importantscattering regions on the terrain. This in turn enables better assessmentof base station sites, antenna pattern selection, sen,iceregion (cell) shaping (handover criteria) and solving networkproblems.Time dispersion is mostly found to be the cause of poor coverageby excluding other possible causes. In cases where fieldstrength coverage does not overlap and base station sites cannotbe moved, shaping antenna directivity will be the only way toeliminate excessive time dispersion.

Aeronautical Public Correspondence (APC) is a telecommtmicationsse!Vice, which enables passengers onboard aircraftto make telecommunication calls to people on the ground.This article describes the terrestrial communications seiVicewhich is based on cellular network for the European CEPTmember countries (CEPT- European Conference of Postaland Telecommunications Administrations) named TerrestrialFlight Telecommunications System (TFTS).This system is a Pan-European System, which means theusage of hannonised frequencies in Europe with hannonisedstandards for the TFTS equipment, which have been issued bythe European Telecommunications Standard Institute (ETSI).Frequencies allocated for TFTS have been designated bythe World Administrative Radio Conference, WARC-92 withfrequency bandwidth of 2x5 MHz:1670- 1675 MHz, for ground to air1800- 1805 MHz, for air to ground.TFTS planning is perfonned by the application of frequencyblocks (42 blocks) with 164 channels in total. Bandwidthof each radio channel, which contains 4 speech channels,is equal to 30.3 kHz.Due to the very high flight of the aircraft (about 13,000 m),it needs a long distance between the centres of cells (radio stationon the ground) to avoid the eo-channel or adjacent channelinteJference.The article presents the planning process with typical cellradius of240km or 350km. In the viewofthatfact, the need ispointed out for finding a compromise solution with regard toemitting power and the influence of interference.Final(v, it is noted that TFTS ground radio stations inCroatia, which are located in Zagreb and Split, may cover theterritory of some neighbouring countries other than Croatia,which is important from the commercial point of view.

The geo-traffic advantages of the Republic of Croatia havenot yet been evaluated as a whole. The traffic-maritime valorisationis included in the strategy of long-term development ofCroatia. This particularly implies the constntction and modernisationof the sophisticated railway and road traffic routesconnecting the Danube region and the Adriatic, especiallyalong the transversal corridor the Danube region - Zagreb -Rijeka - maritime markets, and then towards other maritimeand river ports. At the same time, the application of these technologiesshould be reconstntcted longitudinally from the Westto the East. The container and piggyback terminals and cargotransport centres (RTC) should be primarily constructed, regularcontainer and piggyback trains established and connected,by sea ports and shipping, first of all through the port of Rijeka,with various maritime markets.In this way, higher rationalisation would be achieved, firstof all in traffic, then in economy and the community as a whole,with a far greater traffic safety, environmental protection, majorforeign exchange inflow, etc.