## 4 Results
### Comparative Analysis of CBA Methodologies and Results
#### Calculation of Greenhouse Gas Emissions and Costs According to the CBA Methodology in Austria  
The amount of CBA CO\({}_{2}\) emissions in Austria produced during transport was calculated according to the following equation:  
\[A\ CO_{2}RT=A\ GHG\ M*EF\ CO_{2}=AFC\ V*DF*EF\ CO_{2}\]  
\[A\ CO_{2}RT=109.39\ litres*0.832\frac{kg}{l}*3.15\ kg\frac{CO_{2}}{1}kg\ diesel\ fuel\]  
\[A\ CO_{2}RT=286.688\ kg\ CO_{2}\]  
Note: we consider the DF of diesel fuel according to the HBEFA for Austria as 0.832 kg/L. The greenhouse gas cost (climate protection cost) of road transport was calculated using Equation (S8):  
\[C\ CO_{2}RT=A\ CO_{2}RT\ *UC\ CO_{2}RT=0.286688\ t\ CO2*50\frac{eur}{1}ton\ CO_{2}=14.334\ eur\]  
Calculation of Greenhouse Gas Emissions and Costs According to the CBA Methodology in the Czech Republic  
For the calculation of CO\({}_{2}\)e emissions according to the CBA methodology in the Czech Republic, the CO\({}_{2}\) emission factor for heavy-goods vehicles given in Table 8 was used, and it reached a value of 604 g CO\({}_{2}\)/1 vehicle-km. For the semi-trailer combination used, due to its total weight, we chose the category \"Heavy GV\" and diesel fuel. The amount of CBA CO\({}_{2}\) emissions in the Czech Republic produced during transport was calculated as follows:  
\[A\ CO_{2}\ RT=EF\ CO_{2}\ Vi*DTV_{jkv}=0.604\ kg\frac{CO_{2}}{1}km*295.25\ km\]  
\[A\ CO_{2}\ RT=178.331\ kg\ CO_{2}\]  
\[A\ eCO_{2}\ RT_{i}=178.331\ kg*1+0.00019\ kg*25+0.0159\ kg*298=283.6198\ kg\ eCO_{2}\]  
\[A\ eCO_{2}\ RT_{i}=178.331\ kg*1+0.005\ kg+4.527\ kg=182.863\ kg\ eCO_{2}\]  
The cost of CO\({}_{2}\) greenhouse gas emissions produced during transport according to the CBA in the Czech Republic was calculated as the GHG cost of road transport using Equation (S9):  
\[CGHG\ RT=AGHG\ RT*UCGHG\ RT\]  
\[The\ cost\ of\ greenhouse gas\ emissions=A\ eCO_{2}\ RT*P_{GHG=0}.182863\ t\ eCO_{2}*4061\frac{CZK}{1\ t\ eCO_{2}}\]  
\[A\ CO_{2}RT=109.39\ litres*0.832\frac{kg}{l}*3.15\ kg\frac{CO_{2}}{1}kg\ diesel\ fuel\]0  
Naturally, this study aims to highlight the differences in the ways GHG emissions and climate change costs are calculated and the parameters applied, including emission factors and unit costs of climate change, in the national CBA manuals. These may ultimately influence the results of the GHG analysis when considering specific transport projects in individual countries. The last row of Table 19 provides a percentage comparison of the climate change costs of the model transport using national CBA methodologies. The calculated climate change costs are more than nine times the costs calculated according to the methodology in Hungary, almost four times the costs calculated according to the methodology in Austria, and almost twice the costs calculated according to the methodology in the Czech Republic. Discussion and Proposed Recommendations for Parameters and Their Adjustment in the CBA Methodology in the Slovak Republic  
Regarding the source data on unit costs of pollutants, the CBA methodology in Slovakia is the most up to date of the methodologies compared, based on _EUROPEAN COMMISSION: Handbook on External Cost of Transport_, January 2019. Table 20 compares the density of the superior infrastructure in kilometers per square kilometer of territory, with the Slovak Republic performing below the standard despite moderate growth in recent years. This lower share is also due to the still unfinished infrastructure along the routes of the European transport corridors. This is also one of the reasons why a country comparison analysis has been carried out and shows its importance. Recommendation 1: Proposal to Change the Values of the Fuel Density Used in the Methodological Manual of the CBA in the Slovak Republic, Section 5.2.2.6 (New Manual 4.2.2.6)  
The density values used in the CBA methodology in the Slovak Republic are low and underestimate the results achieved in the area of climate change costing.