Joint probabilistic transition risk across fleet turnover, renewable electricity, and road emissions in New South Wales, 2026–2030

Planning for the transition to low emission vehicles requires more than a forecast of vehicle uptake. This study develops an assessment of transition risk for New South Wales (NSW), Australia, over 2026–2030. Annual indicators describe low emission vehicle uptake, petrol and diesel shares, renewable electricity, road energy use, road emissions, and passenger activity. Forecast ranges for these indicators are linked through independent, Gaussian copula, and Student-t copula assumptions and propagated through Monte Carlo simulation. The results are summarised using event probabilities, a composite transition loss index, and conditional value at risk at the 95 percent tail (CVaR 95 ), supported by robustness checks and bounded scenarios. Petrol and diesel vehicles remain dominant across all dependence assumptions, while the adverse stress tail case produces the greatest downside risk in every robustness variant. A coordinated improvement in uptake, renewable electricity, the decline of petrol and diesel vehicles, and emissions reduces CVaR 95 from 0.438 to 0.299. Faster uptake alone lowers average loss but does not reduce tail risk because the transition loss index identifies cases in which uptake advances without a corresponding improvement in renewable electricity. This result partly reflects the construction of the index and should not be interpreted as evidence that faster uptake is harmful. The findings show that NSW transition monitoring should consider changes in the vehicle fleet, electricity generation, and road emissions together.