There is now increasing literature that examines the downsides and benefits of smart transport infrastructure development. In particular, significant problems arising within urban conurbations can be well addressed given the potential of advanced technology such as Big Data, the Internet of Things (IoT), and Artificial Intelligence (AI). Challenges such as pollution, rapid population growth, and traffic jams can be greatly assisted through such avenues. However, smart transportation projects require expertise and very high levels of funding, and these issues can lead to risks during the implementation phase and the operation stages. Recent literature has canvassed the possibility of using hybrid Public Private Partnership (PPP) models to raise and allocate finance: however, there still remain ‘unknown’ aspects of smart transport infrastructure projects that are not completely addressed, even with careful consideration and detailed evaluation. Thus, the purpose of this paper is to investigate the cost-benefit outcome and determine the major categories of cost-benefit to be considered by PPP investors when investing in ‘smart’ transportation infrastructure. The study used a mini-scoping review focused upon smart transportation infrastructure projects financed by PPP arrangements to create major cost-benefit categories factors. This paper addresses a somewhat unexplored area regarding cost-benefit for data-sharing and integrated technology, and the risks leading to cost overrun in investing in PPP smart transportation infrastructure.