4. Results
Table 3 shows the sustainable development index for the logistics sector (
SDL) in the Visegrad Group from 2008 to 2023, together with its economic dimensions (
EDL), social dimensions (
SocDL), and environmental dimensions (
EnvDL). These indicators were analysed for basic descriptive statistics.
The data indicate that the Czech Republic and Hungary achieve higher indicator values than Poland and Slovakia, indicating a more stable and balanced development in these countries.
The Czech Republic was characterised by high indicator values in all three dimensions from the beginning, with relatively low variability throughout the period, indicating a stable development of the logistics sector. Hungary also achieved relatively high indicator levels, with significant growth in SocDL and EnvDL, although the growth dynamics in these dimensions were somewhat less predictable than in the Czech Republic.
Slovakia recorded the lowest indicator values in 2008 (taking into account all countries studied). The EDL in this country showed significant variability in subsequent years, ranging from very low to relatively high. At the beginning of the study period, Poland was characterised by a relatively low level of development, particularly in EDL, but in subsequent years, a steady increase was observed, primarily in EDL and SocDL.
Descriptive statistics confirm these observations. During the period under review, the Czech Republic achieved the highest average SDL value (0.80) (with low variability, indicating stable and sustainable sector development). Hungary achieved an average of 0.77, significantly improving SocDL and EnvDL. Poland recorded an average value of 0.66 (which may indicate a relatively stable development, with a significant growth of EDL and SocDL). Slovakia, on the other hand, achieved the lowest average SDL value (0.65). Taking into account the countries studied, it is characterised by a relatively lower level of sustainable development in the sector, with progress observed mainly in EnvDL between 2018 and 2023.
Chart 1 presents trend analysis. It confirms that the Czech Republic and Hungary are experiencing strong and stable growth in all areas. Of all countries studied, Poland has experienced the fastest
EDL and
SocDL (the trend fit in these areas is exceptionally high,
R2 above 0.9). At the same time,
EnvDL shows a negative trend and a low fit to the trend line (
R2 = 0.3897), indicating a persistent problem in this dimension. In Slovakia, the highest growth dynamics were observed in
EnvDL, suggesting that it is coming to an end in this dimension, while
SDL is growing more slowly but steadily (
R2 = 0.738).
In summary, the logistics sector of the Visegrad Group is evolving toward greater sustainability, but the pace and balance of this process vary. It is worth emphasising that:
Poland and Slovakia should invest in sustainable logistics and ecoinnovations,
the Czech Republic and Hungary should develop strategies to maintain stability and further modernise the sector (particularly through digitalisation and process automation);
in the Visegrad Group, strengthening synergies between the economic, social, and environmental dimensions is crucial, enabling the logistics sector to meet the challenges of the energy transition and the increasing regulatory requirements of the European Union.
Table 4 presents the renewable energy index (
RE) for the Visegrad Group from 2008 to 2023. This indicator was analysed for basic descriptive statistics.
The data show a significant increase in RE in all countries, although the pace and dynamics of the change vary.
At the beginning of the study period, the Czech Republic had a low RE level (0.38 in 2008), while the other countries recorded values above 0.50. In the following years, the Czech Republic recorded a rapid increase in the index, reaching 0.93 in 2023. In 2008, the RE in Poland was 0.51; in subsequent years, the index systematically increased, reaching 0.98 in 2023. Hungary was characterised by a slower but stable growth rate, from 0.51 in 2008 to 0.94 in 2023. From 2008 to 2023, Slovakia had the highest RE level (approximately 0.80 in 2014 and 0.99 in 2023).
Descriptive statistics indicate that the average share of RE was highest in Slovakia (0.80), followed by the Czech Republic (0.74), Poland (0.73), and Hungary (0.70).
Chart 2 presents trend analysis. It confirms the above observations. During the period analysed, the Czech Republic recorded the highest
RE growth rate (0.0302 per year,
R2 = 0.8815). It can be concluded that it has undergone the greatest energy transformation. Poland and Slovakia also record strong and well-adjusted growth trends (0.0244 and 0.0270, respectively, with
R2 above 0.86). On the other hand, Hungary achieved the lowest growth rate (0.019 per year), but the trend remains stable and well adjusted (
R2 = 0.8047).
In summary, RE grows in all four countries, although the pace of this process varies:
The Czech Republic and Poland—the fastest growth,
Slovakia—a leader in terms of high and relatively stable RE levels,
Hungary—accelerating RE activities,
the Visegrad Group—increased energy security, reduced dependence on fossil fuels, and better adapted to the climate requirements of the European Union.
Table 5 presents the macroeconomic stabilisation index (
M) in the Visegrad group from 2008 to 2023. This indicator was analysed for basic descriptive statistics.
Data show that these indicators are lower and more volatile than SDL and RE.
The values range from 0.27 (Slovakia, 2009) to 0.64 (Hungary, 2017). At the beginning of the period under review, all countries recorded low values (below 0.45) related to the global financial crisis. In the following years, there was improvement, particularly noticeable around 2014–2017, when all countries achieved relatively highest stabilisation levels. Since 2019, declines have been observed again and after 2020 (the COVID-19 pandemic), the indicator values in most countries decreased significantly.
The highest mean of M was in the Czech Republic (0.49), just ahead of Hungary (0.48), Poland (0.46), and Slovakia (0.43).
Chart 3 presents trend analysis. It suggests different developments. The Czech Republic and Hungary have a very low trend line fit (
R2 0.0692 and 0.0185, respectively), indicating that there is no clear trend—the values are rather unstable. An upward trend is observed in Poland (0.0133 per year,
R2 = 0.6247). It indicates a gradual improvement in macroeconomic stability in the long term. In Slovakia, the trend is positive, but poorly fitted (
R2 = 0.0858), indicating significant fluctuations.
In summary, M in the countries studied is relatively low and prone to fluctuations, especially in crises like the pandemic.
In addition, it is necessary to:
The Czech Republic and Hungary—strengthen their ability to manage disruptions,
Slovakia—introduce structural measures to decrease economic vulnerability,
Poland—promote further opportunities for sustainable long-term growth,
The Visegrad Group—harmonise short-term stabilisation efforts with long-term economic development.
Table 6 presents the analysis of the correlation between the Sustainable Development Index (
SDL) and the Renewable Energy Index (
RE), and the Macroeconomic Stabilisation Index (
M) in the Visegrad Group from 2008 to 2023.
Varying correlations were observed, depending on the country and the correlation measure used (all positive).
For SDL and RE, all countries recorded high or moderate correlations (Pearson 0.524–0.915; Spearman 0.585–0.941; Gamma 0.467–0.817; Kendall 0.467–0.817), indicating strong and consistent relationships, linear and monotonic.
In SDL and M, the correlations were lower (Pearson 0.359–0.703; Spearman 0.244–0.694; Gamma 0.200–0.517; Kendall 0.200–0.517), suggesting a weaker relationship between these variables.
The strongest relationship was observed in the Czech Republic for SDL and RE (Spearman 0.941), while the weakest relationship was observed in Hungary and Poland for SDL and M (Gamma and Kendall 0.200, lack of significance).
Overall, the results indicate that the relationships for SDL and RE are significantly stronger than those for SDL and M, with their strength varying between the Visegrad groups.
Table 7 shows the estimation of linear regression models using the least squares method. The impact of the Renewable Energy Index (
RE) and the macroeconomic stabilisation index (
M) on the Sustainable Development of the Logistics Sector (
SDL) in the Visegrad Group was estimated from 2008 to 2023.
The models consider both the current values of the variables and their lags (t−1, t−2, t−3), allowing the temporal effects of energy and macroeconomic policies to be captured.
The models presented meet standard linear regression assumptions. Parameter linearity, lack of perfect multicollinearity, zero expected error, lack of homoscedasticity, lack of autocorrelation of residuals (both first- and second-order), and normality of the residual distribution were confirmed. The test statistics (White, LM, Jarque–Bera) and the p-values indicate that none of the assumptions were violated, ensuring the reliability of the estimate results.
Analysis of the regression coefficients indicates a significant impact of both RE and M on SDL in all countries studied, although some of their effects appear with delay, and the influence of the variables can be positive or negative. The coefficient of determination (R2) confirms the good fit of the models to the data.
In all countries analysed, the impact of RE and M on SDL is clearly differentiated in terms of the strength and nature of the effect.
In the case of RE, the strongest positive impact is observed in Hungary, where RE significantly and clearly strengthens SDL, and in Slovakia, where RE(t−1) plays the most significant role. In the Czech Republic, the effect is also positive, but somewhat weaker and occurs only in a delayed form, suggesting that the economy needs time to adapt to investments in renewable energy sources. Poland, on the other hand, is characterised by high volatility: the RE impact is positive, but in the subsequent period a very strong negative effect appears, only to become positive again with a longer delay. This pattern indicates the transition costs of the energy transition and the delayed adaptation of the logistics sector.
In terms of M, the most favourable current results are achieved in Slovakia, where the coefficient for M is the highest among the studied countries, and in Poland, where the effect is positive, although weaker. M also has a positive and relatively strong effect in Hungary. In the Czech Republic, the impact of M is negative, but a positive effect appears in the subsequent period. This reverse pattern may suggest that stabilisation measures limit the sector’s flexibility in the short term but improve its equilibrium in the long term. At the same time, it is important to emphasise that the Czech Republic has the lowest current impact of M on SDL (M = <0.168), which means that immediate stabilisation measures can initially hinder the development of logistics. However, the strongest negative lagged effect is revealed, M(t−2) = 0.417-indicating that excessive or prolonged macroeconomic stabilisation dampens the dynamics of the logistics sector after some time.
In summary, the data indicate that the development of RE and M is crucial for SDL. Their effects can manifest in the current period and with a certain time lag. RE typically has the highest impact on SDL, especially in the current period or with the first lag. The coefficients for RE are positive and statistically significant in most models, suggesting that RE development strongly supports SDL. Overall, RE has the most significant and stable impact on the SDL, while M has a smaller and more variable impact over time, depending on the lags and the model’s specificity.
Table 8 presents the estimation of multi-equation regression models using the Seemingly Unrelated Regression (SUR) method for the Visegrad Group from 2008 to 2023. The interrelationships of three dimensions of sustainable development of the logistics sector (
SDL), economic (
EDL), social (
SocDL) and environmental (
EnvDL), were analysed in the context of the impact of renewable energy sources (
RE) and macroeconomic stabilisation (
M). The models consider both the current values of variables and their time lags (
t − 1,
t − 2), which allows capturing the dynamic effects of energy and macroeconomic policies.
Analysis of the regression coefficients indicates significant associations between all dimensions of SDL in each of the countries studied, with the nature and strength of the effects varying between countries.
All models have a high R2 and meet standard SUR assumptions. All OLS and SUR models used in the analysis met standard estimation assumptions, confirming their statistical validity and inferential reliability. Diagnostic tests for individual countries revealed no issues with residual autocorrelation (Durbin–Watson test, LM) or heteroscedasticity (White test), meaning that the variance of the random component is constant and the relationships between variables are not distorted by model errors. Furthermore, the Jarque–Bera test confirmed the normal distribution of residuals, which increases the reliability of the parameter significance tests used.
In the SUR multi-equation models, the Breusch–Pagan test results indicate significant interdependencies between the equations for the individual dimensions of sustainability in the logistics sector (SDL, EDL, SocDL, EnvDL). This indicates that the use of the SUR method was justified and statistically valid, as it allows for the interdependence of errors between the equations and thus increases the efficiency of parameter estimation.
High values of the coefficient of determination R2 (0.7–0.96) confirm that the models explain the variability of the examined SDL indicators very well, while the lack of violations of the basic regression assumptions indicates the stability and reliability of the obtained results.
In the Czech Republic, EDL positively affects SocDL and EnvDL, while RE reduces EDL, and M has a positive effect in the current period but a negative effect in subsequent periods. In SocDL, EDL strongly supports social development, EnvDL has a negative effect, and RE and M have positive effects. In EnvDL, EDL has a positive effect, SocDL has a negative effect, RE has a significantly positive effect in the current and lagged periods, and M has a weakly positive effect.
In Hungary, EDL positively affects SocDL, while RE has a mixed effect on EDL, negative with a one-period delay but positive after two periods, and M has a negative effect in the current period. In SocDL, EDL supports SocDL and SocDL(t−1), RE has a time-varying effect (negative in the current period, positive with lag) and M has both a negative and positive effect in subsequent periods. In EnvDL, EDL has a negative effect, SocDL has a mixed effect (negative in the lagged period), and RE and M have a positive effect in the lagged periods.
In Poland, EDL has a mixed effect on SocDL and EnvDL. In SocDL, EDL negatively affects lagged periods, while in EnvDL, EDL significantly limits environmental development. RE has a predominantly positive effect on SocDL, although it may have a negative effect in lagged periods, while on EDL and EnvDL, the effects are mixed or negative in some lags. M supports EDL, SocDL, and EnvDL in most periods, although the impact may become apparent with a delay.
In Slovakia, EDL positively influences SocDL in the lagged period but has a negative impact in the current period. EnvDL supports EDL and is also reinforced by RE in the lagged period, while M has a mainly negative impact on EDL and EnvDL in the short and medium term. In SocDL, RE has a positive impact in current and lagged periods, while the impact of EDL and M is revealed in lags, and EnvDL has a negative impact.
Analysis of SUR models for the Visegrad Group indicates that EDL strongly supports SocDL and EnvDL, although its environmental impact can be limited in some countries. RE positively impacts SocDL and EnvDL (these effects often manifest with a delay). M operates differently over time—in some cases, it supports all dimensions of SDL, while in others, it can limit them (especially in the short term). The results obtained stress the importance of acknowledging the temporal dimensions of RE and M. At the same time, they indicate the need for strategic planning of energy and macroeconomic policies to support sustainable development of logistics effectively.
The countries in the Visegrad group are developing their logistics sectors towards greater sustainability, although the pace and balance of this process vary. An increase in the use of renewable energy sources is visible across the region, strengthening energy security and supporting climate change in line with EU policy. The greatest challenge remains the weak and volatile macroeconomic stability that limits development predictability. In general, the Visegrad Group has the potential to become a major hub for green and innovative logistics in Europe, provided that economic, energy, and environmental policies are better coordinated.