Table 1.
Variables.
| Variable | Definition/Measurement | Reference | Source |
|---|---|---|---|
| Dependent Variable | |||
| Environment Sustainability (ES) | Adjusted net savings (excluding particular carbon emissions) | Huo et al. [6] | WDI |
| Independent Variables | |||
| Road Infrastructure (RIN) | “Total length of roads” | Baloch and Suad [35] | NBS |
| Road Density (RDN) | “Total length of roads/population” | Aljoufie [12] | NBS |
| Road Transport Energy Consumption (RTEC) | “Road energy consumption (Kg of oil equivalent per capita)” | Baloch and Suad [35] | WDI |
| Energy Intensity (EIN) | “Road energy consumption/GDP” | Baloch and Suad [35] | WDI |
| Moderating Variable | |||
| Population Density (PDN) | “Population density (people per sq. km of land area)” | Baloch and Suad [35], Aljoufie [12] | WDI |
| Control Variable | |||
| Economic Growth (EGR) | “Per capita GDP (current US$)” | Chen and Lin [4] | WDI |
Note: “WDI: World Development Indicators, NBS: National Bureau of Statistics; Global Footprint Network”.