Autonomous vehicles (AVs) not only can reduce traffic accidents and congestion, but also can change land use, architecture design and mode choice behaviours. In preparation for the age of self-driving vehicles, this study explores the impact of autonomous vehicles on various urban environment and suggests policy strategies for the city of Seoul.

First, we investigated changes of road space by AVs and found that current roads in Seoul might remain relatively the same even in the self-driving age. Significantly, downtown corridors affected by signalised intersections have limitations in increasing road capacity with Avs. Thus, less than 1% of roads in Seoul have potential to reduce one lane when traffic demand remains the same. Rather, traffic demand tends to increase significantly with AVs by increasing the utility of passenger vehicles and decreasing travel time value. With demand change and different user behaviours with AVs, road space needs to introduce additional space such as 'Flex Zone.'

 On the other hand, parking space in downtown Seoul has potential to be shifted with AVs. Capacity of parking lots can increase with unmanned parking technologies, whereas parking demand will decrease significantly with shared-mobility services. Since attached parking lots with increased capacity can accommodate the parking demand, current on- and off-road parking space in downtown could be converted to other land uses. The revenue from a land use transition could be utilised for reserving additional parking space in residential areas in Seoul that still suffer from parking space shortage. 
 This study also suggests that future transportation in Seoul should be a shared-mobility (or public transportation) oriented system in the age of AVs so that all citizens could share benefits of AVs together. If the traffic system is developed based on privately-owned AVs, traffic congestion in Seoul will be as severe as today. To have a shared-mobility-oriented system, the service level of public transportation should be improved with cutting-edge technologies such as demand response service and/or optimal dynamic routes by artificial intelligence. In addition, a substantial reduction in fare rate of Seoul public transportation should be considered to minimise social cost of traffic congestion with private vehicles. 

Above all, changes by AVs should be addressed with an integrated system, including transportation, urban planning and architectural designs. Expected problems cannot be solved with only transportation view or physical infrastructure improvement. With an integrated system, Seoul can be a smart city that can solve current urban problems with an autonomous driving technology.