The paper deals with the effects of electromagnetic fields upon participants in postal traffic (employees and users). The authors first provide a general review of the effects of electromagnetic fields upon people, and then a special reference is drawn to the examination of properties of non-ionizing electromagnetic fields (of particular intensity with postal radio relay facilities), possible harmful effects of subject fields upon people, and individual aspects of protection and their efficiency.

Traffic infrastructure makes an integral part of the traffic and economic system of each country. The designers of traffic infrastructure investment policy have to meet the requirement for this policy to be based on scientific developments and synchronized activity of all economic system segments. In the article the accent is assigned to the development and integration capability of traffic infrastructure facilities.

The Article offers a complete model for calculation of emission of harmful components from motor vehicles driven by Otto motor and supplied with three-way catalyst. The calculation model contains several parts. The starting base makes the determination of load of the motor, i.e. torque and speed in order to overcome the imposed resistance of driving. Then there follows a complete thermodynamic calculation process with the motor cylinder for the necessary load. Emission of harmful components at the motor outlet is calculated from the balance state of gas at the combustion end. Finally emission of harmful components after the three-way catalyst outlet taking into account its efficiency. Using this model calculation for vehicle VW Passat driven by Otto motor of volume 2000 cm2 with a three-way catalyst performed in the article. Working regimes are taken according to the vehicle cycle of the Europe-test.