Collection and transportation within the system of solid waste management may account more than 60% of the overall budget, most of which is for fuel costs. Furthermore, municipal vehicles have great environmental impact through exhaust gases emissions. The aim of this research was to estimate the potential for reduction of fuel consumption and thus the emission of CO2 through the communal vehicles route optimization. General methodology for route optimization is also presented. For the area under study, detailed field experimental research in the City of Kragujevac was conducted. Using GIS and GPS technology, whole municipally infrastructure for waste collection was scanned and all paths of communal tracks was recorded and allocated in developed database. Based on experimental and numerical results, one typical municipal vehicle route was analyzed by using ArcGis software. The obtained result indicates 2700 km of possible savings per year concerning one communal vehicle. In addition, the most fuel-economical route was extracted and compared with the original route, and with the routes extracted from criterions concerning the traffic time and shortest distance. According to available information for the City of Kragujevac and the results from this study, it was estimated that the total savings could be 20% in costs and the associated emissions.

Based on a critical review of the previous research and the comprehensive theoretical analysis of all functional parts of two-stage electrohydraulic servovalves with a spool position feedback (a current amplifier, a torque motor, the first and the second stage of hydraulic amplification) a detailed mathematical model of the servovalves was created. The analysis was based on the fundamental laws of electromagnetism, fluid mechanics and general mechanics. The model parameters are physical quantities and the complexity of the model is only limited by the possibility of the correct numerical integration. It includes phenomena and quantities that are of influence on the behaviour of the servovalves, so it can predict their function in a wide range of expected working regimes. Results obtained with the numerical modelling on a personal computer were compared with the appropriate experimental data and the validity of the proposed model was confirmed with satisfactory accuracy.