## 5 Discussion and Conclusions  
The decision to purchase a new asphalt mixing plant and to renew the asphalt mixing plant fleet is a complex one which requires detailed strategic planning, a SWOT analysis and the consideration of long-term effects. If the newly installed asphalt mixing plant is not going to produce asphalt mixture most of the time, the renewal of the fleet can lead to significant long-term financial losses or other undesirable consequences. In this work, it was assumed and proved that the level of the utilisation of the currently used asphalt mixing plants, i.e., the amount of the produced asphalt mixture in the currently used asphalt mixing plants, is a proper indicator to define the actual need for new asphalt mixing plants in the country. During the analysis it was found that the annual average amount of the asphalt mixture produced across 30 European countries during the period of the last 12 years (2005 to 2016) ranged from 0.3 million (Iceland) to 47.25 million tonnes (Germany). The estimated amount of asphalt mixture produced per asphalt mixing plant in each of the 30 European countries ranges from 22,575 (Greece) to 217,773 tonnes (the Netherlands). Almost a 10-times difference in the average amount of asphalt mixture produced in a single AMP, while taking into consideration different European countries, can be seen. Based on the performed research, it is very likely that the reason for an almost 10-times difference between the asphalt mixtures produced in individual countries is due to the varying mixing capacities of their technological facilities. It was determined that the average mixing capacity for all the asphalt mixing plants in the European countries is 68,530 t/year, the standard deviation of the mixing capacity is 39,400 t/year, and the data distribution is not normal. Furthermore, the analysis showed that the lowest amounts of asphalt mixture produced in Europe are those that come out of the asphalt mixing plants of Lithuania (39,250 t), Switzerland (38,322 t), Hungary (37,108 t), Iceland (32,728 t), Latvia (24,691 t) and Greece (22,575 t). As a result, it can be stated that too many asphalt mixing plants can be found in each of these countries. Based on these results, it can be stated that the ongoing renovation of the asphalt mixing plants' fleet in Europe needs to be reconsidered. The need for clearly defined criteria to serve as guidelines for the decision-making process of an asphalt mixing plant's fleet renewal strategy provides an important research problem. This works contributes to the solving of this issue. The main contribution of this work is the proposal of a novel nine criteria system applying to the decision-making process for the purchase of an asphalt mixing plant. The significance of these criteria was determined after the presentation of a case study. Based on this research, the following conclusions are formulated:  
1. The research has shown that the differences between the minimum and maximum annual amounts of asphalt mixture produced and the differences between the average annual numbers of the operating asphalt mixing plants in different European countries are very high. Based on the significant difference, asphalt mixture production across the 30 European countries was categorized into five categories: (1) very large quantities (from 30 to 50 million tonnes, four countries in Europe); (2) large quantities (from 15 to 30 million tonnes, three countries); (3) average quantities (from 5 to 15 million tonnes, nine countries); (4) small quantities (from 2 to 5 million tonnes, seven countries); and (5) minimal quantities (from 0.25 to 2 million tonnes, seven countries). The average annual minimum number of asphalt mixing plants in operation in these countries was 4.2 (Luxembourg) and the highest average number was 652.2 (Italy). 2. It was determined that the correlation between the number of asphalt mixing plants and the production of asphalt mixture in European countries is a positive linear correlation with the coefficient of determination \(R^{2}=0.9122\).