This is a paid asset, but now you can download Enter Exit Vehicle Networked Free.
Detail this asset from Unity Store: Original Link
Enter Exit Vehicle Networked v4.3 (Latest version)
“If possible, please buy the package to support the developer”
Warning “BattlePhaze Enter Exit Vehicles” is an enter exit solution for photon 2.0 Networking
BattlePhaze Enter Exit is a powerful system that goes between the car and the player. the enter exit is based on Transferring Ownership but on a much bigger scale.
currently, Enter Exit Supports: Unlimited amount of seats, Seat Based Scripts and Cameras, Messages when failing to move a player between Seats or trying to enter the vehicle.
youtube demo can be found below Demo
for any more details feel free to contact me at Email Address