Autonomous transportation ecosystems represent one of the most significant technological transformations of the 21st century. Combining self-driving vehicles, smart infrastructure, and governance frameworks, these systems promise safer, more efficient, and environmentally sustainable mobility solutions. However, their integration introduces complex engineering, regulatory, and ethical challenges. This paper explores the development of autonomous vehicles (AVs), the role of smart roads in enabling vehicle-to-infrastructure communication, and the critical need for governance models that balance innovation with public trust. Key engineering challenges include sensor fusion, machine learning reliability, cybersecurity, and real-time decision-making. Smart roads—equipped with Internet of Things (IoT) technologies, adaptive signaling, and embedded sensors—are essential for supporting AV deployment at scale. Ethical concerns surrounding liability, data privacy, and algorithmic decision-making highlight the importance of transparent governance structures. Opportunities lie in reducing traffic accidents, lowering carbon emissions, and reshaping urban mobility. Together, these innovations point toward a future where autonomous ecosystems redefine transportation as a collaborative, intelligent, and human-centered system.