Not having a clue (yet genuinely curious) I asked my friend Mike (retired Electrical Engineer who spent over 40 years working for Lockheed) his opinion, and gave the picture you posted, and he said it's likely there is a chute/elevator/lift built onto the side of the building which the cars back into and out of. It seems simple enough, and when I pressed about the added weight of the vehicles he stated with a curb weight of not more than 4k lbs the vehicles themselves (presuming not more than 4 or 8 per floor) really would not add much in the way of weight in relation to the weight of the steel and concrete used for each floor.
My theory is that only the penthouses have this luxury, it is not available to every single condo, my presumption based on the fact that elevators designed to transport something very heavy and very valuable (and also inherrantly very dangerous if anything gets weird/ustable) are typically very slow, and rich people hate waiting for things like elevators moving their cars. Mike says it's not feasible for there to be more than 1 chute per side of the building, so you could be on the top floor and literally waiting hours while the people below you also wait in line to get your car out. I just do not see this happening, thus it's much more logical that only the best of the best enjoy such a unique luxury.
As I hate leaving questions half answered (or, in this case, pretty much guessed at) I decided to just go to the source and emailed
admin@bkkcondo.com, will copy and paste a more official response when I have one, so far I got the following:
Jane Bkkcondos
10:00 PM (41 minutes ago)
to me
Thank you for your email.
We received your message that you sent to
admin@bkkcondos.com.
One of our staff members will reply to you as soon as possible;
USUALLY within 24 hours (Mon-Fri)
(Time zone: GMT +07:00 - Bangkok Thailand)
If in any event you do not hear back from us within 24 hours
(Mon-Fri), please call us or resend your email.
Warm regards,
BKKCondos co., Ltd.
T (+66) 2 2532663
F (+66) 2 6511699
www.bkkcondos.com
admin@bkkcondos.com
19/123 Sukhumvit soi 13
Wattana
10110 Bangkok
Thailand