###### Abstract  
Mobility is experiencing a revolution, as advanced communications, computers with big data capacities, efficient networks of sensors, and signals, are developing value-added applications such as intelligent spaces and autonomous vehicles. Another new technology that is both promising and might even be pervasive for faster, safer and more environmentally-friendly public transport (PT) is the development of autonomous vehicles (AVs). This study aims to understand the state of the current research on the artificially intelligent transportation system (ITS) and AVs through a critical evaluation of peer-reviewed literature. This study's findings revealed that the majority of existing research (around 82% of studies) focused on AVs. Results show that AVs can potentially reduce more than 80% of pollutant emissions per mile if powered by alternate energy resources (e.g., natural gas, biofuel, electricity, hydrogen cells, etc.). Not only can private vehicle ownership be cut down by bringing in ridesharing but the average vehicle miles travelled (VMT) should also be reduced through improved PT. The main benefits of AV adoption were reported in the literature to be travel time, traffic congestion, cost and environmental factors. Findings revealed barriers such as technological uncertainties, lack of regulation, unawareness among stakeholders and privacy and security concerns, along with the fact that lack of simulation and empirical modelling data from pilot studies limit the application. AV-PT was also found to be the most sustainable strategy in dense urban areas to shift the heavy trip load from private vehicles. autonomous cars; urban mobility; rapid bus transport; greenhouse gas (GHG) emissions; energy conservation +
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For example, the VAA programme demonstrated a Level 2 in the US state of Oregon, that is, precision docking and lane adherence by the steering automation, while with the manned braking and throttling of on-transit bus. Figure 1, prepared after [PERSON] [5], covers the state of research on the autonomous transportations systems in urban areas around the world based upon the vehicular size, capacity and operational features. On the note of autonomous buses, CityMobil2 is an innovative PT project, tested at the University La Sapienza in Rome to investigate the feasibility of autonomous public transit by studying the shared and on-demand mobility on an automated guideway transit, road user interactions and bus user experiences, where a considerably positive outlook from the public (See Section 2.3) was observed. Automated guideway transit was defined by [PERSON] [6] and [PERSON] et al. [1] as a mode of urban transportation where dedicated tracks are used for the operation of completely autonomous vehicles. In the case of autonomous personal transportation, companies such as Volvo and Nissan have expressed interest in commercially marketing autonomous vehicles by the year 2020 [7; 8]. While according to Google co-founder [PERSON], autonomous vehicles may be a reality on U.S roads within the next five years [9] or so. Researchers such as [PERSON] [10] and [PERSON] and [PERSON] [11] proposed that the operation of autonomous personal cars may result in safer and less congested travel. As already evidenced by the increased fuel savings, roadway capacity, accident aversion and lower emissions are now due to the introduction of some level of automation (e.g., assisted parking and adaptive cruise control) in newer cars. Apart from fully automated cars such as Massachusetts Institute of Technology (MIT)'s fully autonomous Land Rover LR3 Talos [12], shared autonomous vehicles (SAVs) have also been researched as an extension of the emerging e-hail or car-sharing [13].