Big Data in transport and mobility is expanding rapidly, driven by the increased data-collection capabilities of modern vehicles, enhanced data-sharing between vehicles and infrastructure, and emerging mobility technologies that both rely on and generate vast amounts of data during operation. Promised benefits, including reductions in road fatalities, energy consumption, and congestion, as well as the development of new mobility modes, offer substantial value for society, the environment, and the economy. However, realising this potential requires a holistic, adaptive legal framework capable of addressing risks to safety, liability, and privacy. This chapter finds that current safety regulations lack specific mechanisms for managing risks arising from data quality issues in large transportation datasets. It further concludes that liability disputes involving Big Data–based products will be highly data-centric and may impose significant practical burdens on future plaintiffs. Privacy risks are also likely to intensify as modern vehicles increasingly collect extensive categories of personal data, often used beyond the scope of consent given by data subjects. The chapter ultimately argues that existing legal regimes must evolve clearer standards for data governance and accountability, and that the law should leverage technology as much as it seeks to regulate and shape it.