Transport's GHG emissions persistently rise, contrasting sectors where interventions have stabilised or reduced emissions. This reflects the complexity of reducing emissions in a sector tied to economic growth, urging advancement beyond high-level models to tailored, accurate, and robust policy impact estimates on transport activity and GHG emissions. Addressing this, PATH2ZERO equips stakeholders with a comprehensive knowledge base for developing, evaluating, and benchmarking net-zero transport pathways, incorporating cross-sectoral assessments and promoting global collaboration. Employing a sophisticated methodology, in the first cycle, it harmonises data and maps, describes, validates, and quantifies EU policy elements, serving as modeling input (introducing "P2Z_DataSyncer" for data alignment and "P2Z_PolicyFrameMapper" for policy visualisation). An advanced model framework forecasts transport sector activity and emissions to 2050, integrating them across other sectors and countries for thorough GHG reduction evaluations including fairness and economic impact (developing "P2Z_Forecaster" for predictive modeling). Benchmarking follows to identify strategic gaps for achieving GHG targets per European and international targets, enhancing policy alignment and scenario comparisons (producing "P2Z_Evaluator" for policy effectiveness evaluation and "P2Z_Benchmarker" for pathway benchmarking). In the second cycle, PATH2ZERO refines national and cross-national policies for stricter policy frameworks, culminating in integrated, benchmarked pathways that inform EU strategies (generating "P2Z_PolicyFrameFinder" for policy framework development and "P2Z_SectoralAdviser" for sector integration). PATH2ZERO's collaborative approach, involving national and international stakeholder co-creation, ensures diverse, feasible and best-practice-informed net-zero pathway development (creating "P2Z_Engager" for stakeholder engagement and "P2Z_Tool" for impact visualization).