## 6 Conclusions  
The integration of the P&R system in the activity plans of travelers encourages conventional private cars to park their cars outside of the city center of Budapest. The city center has specific regulations that add extra costs to the travel utility of daily travelers, especially workers and shoppers. The impact of the P&R system on the travel behavior of users was assessed in this paper. Moreover, AVs are a promising technology that may create several opportunities for certain groups to use private cars, without use restrictions, such as a driving license. Thus, a simulation of the existing transport modes of travelers and the P&R system was run using the MATSim software, including conventional private cars, public transport, and AVs. Four scenarios were simulated, including (1) the existing transport mode (cars), which compromised existing daily activity plans of travelers, (2) the existing transport mode with AVs, (3) the existing transport mode with the integration of the P&R system, where travelers park their cars at the nearest P&R facility to their destination and switch to public transport, and (4) the P&R system, with AVs as a feeder system to public transport (conventional private cars in scenario 3 are replaced by AVs). In conclusion, the result showed that the P&R system increased the overall travel time of travelers, compared with travelers' existing transport modes. In the P&R system, the parking process time was reduced, because the travelers could park their cars, rather than search for parking spaces in the city center, and the cost of parking was less at the P&R facility, compared with that in the city center. Moreover, the results demonstrated that using AVs as a transport mode to replace personal cars reduced travel time, because the number of vehicles on the road network was reduced, and the parking process time was removed. In this regard, AVs can transport travelers to the location of P&R facilities and park there (if they are not called), and this strategy can decrease the size of the P&R facilities.  
The limitations of this study are: (1) the study used a sample size that only covered only the Budapest city and did not include the travelers who come to the city from other cities and towns. In this regard, a recommendation for making a wider survey to include the large size of sample size that considers the travelers from outside of Budapest; (2) the results of this study were produced based on the current transportation system--especially the schedule of public transport network and lines--as well as the road network, and changes in this would change the results of this study; (3) the study used the existing P&R facilities in Budapest, whereas constructing new facilities would change the result negatively or positively, which leads to the importance of conducting a simulation study to evaluate and optimize the locations of the proposed P&R facilities; and (4) the locations of the activities of the travelers and the characteristics of trips and travelers affect the result of the simulations conducted in this paper in terms of the AV fleet size, travel time, P&R strategy (management and operational process), and travel distance. Therefore, future researches based on the limitations of this study are recommended.  
Conceptualization, J.H.; formal analysis, J.H.; investigation, J.O., D.E.-K. and J.T.; supervision, D.E.-K. and J.T.; writing--original draft, J.O.; writing--review and editing, J.H. All authors have read and agreed to the published version of the manuscript. This research received no funding.  
The research was supported by the BKK Centre for Budapest Transport, providing travel data collected through the EFM Unified Transport Model of Budapest.  
The authors declare no conflict of interest.