Abstract:Advance mitigation has attracted attention for its potential to improve ecological outcomes of and to reduce transportation agency expenditures for compensatory environmental mitigation. When devel-oping or improving infrastructure in ways that impact habitats and species, transportation agencies are required to avoid, minimize, and mitigate natural resource impacts through compensatory mitigation. Whereas agencies traditionally plan and implement compensatory mitigation project-by-project, late in project development, advance mitigation addresses the impacts of one or many transportation projects before or during project planning. This new practice may reduce infrastructure development costs, yet evidence of its associated cost savings has been piecemeal and often anecdotal. We explore the early acquisition of land for compensatory mitigation as one advance mitigation strategy that may reduce costs. With case-based analysis of California's Beach Lake Mitigation Bank, we provide post hoc empirical estimates of savings realized from advance purchase. Additionally, hypothetical scenarios illustrate how the timing of mitigation land purchases can impact cost. Overall, we provide new evidence that advance mitigation, speciï¬cally early acquisition of land for compensatory mitigation, could promise agency cost savings, particularly when land is purchased during a market trough instead of at market peak. Still, inevitable project planning and land market uncertainties necessitate cautious optimism.