## 5 Discussion
### Research Directions  
Few studies identified in this review considered the six smart mobility innovations together as a broad driver for change in the transportation system. Given that alternative fuel vehicles, such as battery electric and hybrid electric, and ITS have already started to be introduced into urban areas, and trials of AV are prevalent throughout the world, it is problematic to analyze each of these technological drivers as individual entities that will not interact and influence the success, or failure, of each other. The management of these technological innovations is therefore necessary to harness their benefits in response to transport disadvantage. That is why new operational structures and ways of looking at the transportation system including DRT, shared mobility, and MaaS remain important. Nonetheless, while DRT systems are not new and have been implemented throughout the world--as an alternative to public transport and targeted toward those experiencing disadvantage--it has developed a stigma whereby it is often viewed as an option for only the aged and disabled. Similarly, shared mobility offered by private industry including ride-sharing, car-sharing, and FFM are typically targeted towards users in centralized, denser areas where the highest demand is available to ensure maximum profit. These services, therefore, rarely benefit those experiencing transport disadvantage, and often only exacerbate existing issues with unequal accessibility. As an integrated service, MaaS represents a new way of branding DRT, while enhancing public transport, shared mobility, and other elements of the transportation system. Furthermore, MaaS presents a unique opportunity to provide the platform from which new innovations are introduced into market, the data analyzed, shared, and used to assess its suitability for alleviating transport disadvantage, and other related issues. Prospective research should, hence, look at ways to use MaaS to harness the benefits of smart mobility innovations and attract users to shared mobility and public transport. MaaS is a relatively new topic so further research could focus on the barriers, and risks associated with implementing MaaS within urban areas. Analysis throughout a range of case study areas using transportation modeling, consumer surveys, expert opinion, and trials could also identify issues specific to the varying characteristics of different regions, including those associated with regulatory systems, policy frameworks, cultural differences, and geographic conditions. Secondly, research could also focus on other innovative ways to integrate transportation modes, attract users to shared mobility, or develop alternatives systems. Research could explore the role of other technological advances outside the field of transportation including 5G, AI, digital twins, virtual reality, blockchain, IoT, big data, and cloud computing. For example, the use of virtual reality and augmented reality could be used to educate, market, and promote new transportation innovations towards individuals and business. Similarly, it could be used to let users experience new transportation technology prior to analyzing their attitudes. Finally, given the recent events associated with the COVID-19 pandemic and its potential implication on consumer attitudes towards shared mobility, there is also a need to analyze whether the experience has changed user perspectives and willingness-to-ride shared, and public transport. This is important as attitudes may be changing due to increased awareness of vulnerabilities associated with virus transmission from passengers sharing close quarters in vehicles that often rely on centralized air-conditioning and little ventilation [138]. Furthermore, given these unprecedented events and the pressure on individuals and business to quickly adopt remote working and social environments transportation researchers may be more inclined to ask whether no mobility is smarter than smart mobility.