This is definitely a neat holster...but maybe it's just me being a skeptic...
I have seen a lot of car crashes. The position you should be in and the space around your body in a vehicle is supposed to be a certain way to give you the maximum benefit of the car's safety features. I would hate to see a broken tibia/fibula/kneecap/femur or a life/limb endangering laceration to the leg because the space for your legs has just drastically been reduced. Just like self defense, we usually don't decide when a car crash is going to happen, the time chooses us. It's all risk vs benefit, to each his own.