Disagree completely. I'd ditch the vehicle option. If the earliest forecast is for this to be built in seven years, how much will the driving landscape change in that time? Robo-cars even? This is primarily for commuters who can walk/taxi/rent at the destination. Even travellers will do the same.
If you want to take your car, drive it IMO. When you fly, there is no expectation of taking your car along with you and this should be similar - focus on what we will need rather than on what a minority could fancy.
I agree to your point about taking your actual car. Loading cars inside would indeed complicate the system a lot.
What I tried to say was more about the psychological impact of imagining a car fit in the capsule, even if the same space is just taken by larger seats.
If you want to take your car, drive it IMO. When you fly, there is no expectation of taking your car along with you and this should be similar - focus on what we will need rather than on what a minority could fancy.