Evaluating Sustainable Green Road and Green Belt Practices in Sragen Regency: A Delphi-Based Assessment

Sustainable road rating systems are increasingly adopted globally; however, their effectiveness as reliable assessment tools often require deeper empirical validation. This study quantitatively evaluated a certified green road in Sragen Regency, Indonesia, by statistically linking on-the-ground ecological data to its assessment score. A validated Delphi-based instrument (n = 17 experts, Cronbach's α = 0.987) was used for the assessment. Roadside vegetation was surveyed at five points to calculate landscape (gamma) and local (alpha) biodiversity using the Shannon Index, with a onesample t-test assessing local diversity significance against an ecological benchmark (H’ = 1.5, indicating moderate biodiversity). The road achieved a three-star certification with a score of 39.55.However, a critical discrepancy emerged: while landscape-level diversity was high (H'γ = 2.24), the mean local diversity was statistically low (H'α = 0.78, p < 0.001), a paradox explained by high species turnover between sites. This study concludes that certification scores can mask significant ecological weaknesses. High landscape diversity does not equate to healthy local ecosystems, highlighting thecritical need for multi-scale metrics in rating systems to accurately reflect on-the-ground sustainability.