Integrating a range of complementary energy models is becoming an increasingly common method for informing low carbon energy pathways at both national and global levels. Multi-modelling approaches facilitate improved understanding of the detailed technology pathways required to meet decarbonisation targets; however, to-date there has been limited attention on the policy roadmaps and enabling measures that might achieve these decarbonisation targets. This paper addresses this gap by developing a multi-model approach using an energy systems optimisation model, a sectoral simulation model together with scrutiny of individual policy measures to explore decarbonisation of the private car sector in the Irish transport system commensurate with an 80% reduction in national carbon emissions by 2050. The results comprise a cost optimal technology pathway for private cars in a future energy system constrained by a maximum level of carbon emissions, a policy roadmap identifying annual changes in energy efficiency, renewable energy and electrification, and a suite of enabling measures including changes to vehicle registration tax, a biofuel obligation on suppliers and a suite of measures to increase the share of electric vehicles in the fleet. The level of confidence in the different enabling measures to achieve the policy goals is compared and discussed.