Naoya8: There's a lot about cars and bikes in general that needs more work:
- car horn being useless (as you mentioned),
- weak lights (as you mentioned),
- terrible driving controls on KB/M (can't steer with mouse and constantly tapping accelerate or turn keys is complete opposite of immersiv, looking back doesn't work),
- can't deccelerate smoothly on KB/M without "tapping" [spacebar] or [S] keys, which often ends up with losing control,
- lack of back mirrors (seriously, I'd love to drive cars in first-person but how the hell am I supposed to know if it's safe to change lanes? It's a bit better on bikes),
- customization options (I love my Akira-esque Yaiba Kusanagi, but my V is a corp and I'd like to get rid of this unfitting paintjob),
- AI drives rather bad (sometimes problems with pathing, they stop even without any cars nearby to collide with and with green lights, won't start driving once red lights turns green, ignore horns, etc.).
I'm okay with driving physics (even if it's a bit annoying), but points above are must-fix for me.
don't forget that it seems that you can't even use the bikes stash, or at least I haven't been able to use my bikes stash at all, I have items in the stash but the bike shows as empty and when I try and put anyting in nothing happens.