Maybe at some point you should suggest to your friend that they start taking driving more seriously before they kill someone.

I'd be stunned if they haven't injured someone yet.

I just don't get how "bad driver" is a haw-haw thing instead of a "what the hell wrong with you" thing.

It's both. I try to exert some good influence where I can, but in general I do worry a lot about that particular friend.

My initial response was to suggest that next time you do anything like truth-or-dare, dare him to install a dashcam and press the save button and send you the footage every time. But that's obviously not really going to have a hilarious endgame at the end of the day, it's not like it'd be a lucky dashcam that's always in the right place at the right time capturing other cars. It'd just be awkward for everyone.

Objectively speaking (in the interests of constructive assistance) I wonder if this person may be somewhere around "low but definitely non-zero" on the Kevin Spectrum (ad-hoc definition taken from https://old.reddit.com/r/AskReddit/comments/219w2o//cgbhkwp/). If relevant, my next thought is whether some degree of cognitive issues may run in the family.

I've noticed that one of the significant impacts of the developmental delays and perpetual catchup associated with my high-functioning autism has been a deeply-ingrained awareness of not just feeling "behind the curve" like I'm perpetually scrambling to keep up, but having hard evidence left right and center that I really am not simply Getting Gud.

If this person grew up in either a hostile environment that cultivated a belief that it was impossible to ever do anything right, or simply a situation devoid of leadership to the extent he was left going round in circles due to lack of (for want of a better way to say it) developmental autocue, I could totally see some really terrible social anxiety, self-loathing, social detachment, and compounded awkwardness and depression developing from that.

Getting traffic-jammed at the entry to a speedway that always seems too fast to merge onto, or stuck in front of a street curb with duckling legs that never grow to the point of scaling, can have an impact over the long term - The Show Must Go On, and staying relevant isn't really a question in the fight for survival, so the only really viable option is to hack it and pretend that everything mostly works.

Extrapolating this status quo and envisaging the worst-case-scenario end state, I'd imagine it would be like waking up one day and realizing the biggest themes in my life were a) the giant delta between how much I pretend to have sorted out and what I can really keep up with, b) how much I'm pretty much blindly depending on some circumstantial alignment to happen soon to provide some opportunity to catch up and maybe get some confidence, c) the terrifyingly disproportionate amount of calling life's bluff I'm doing on a regular basis and d) how much I have have to cram this stuff into the nearest can and sit on the lid in order to cope.

If the situation I was in resembled the above, attempting to discuss it (particularly considering (d)) would probably produce a reactive and shouty mess. It would be very difficult. But it could prove life-saving.