Is like to help but I don't know which one.
I tried the Car accident tag on Baka updates and here's what I got. (Hopefully, If someone's tagged it, it should be there)
https://www.mangaupdates.com/series.html?category=Car%2Baccident%2B&genre=Yaoi&exclude_genre=Doujinshi&filter=some_releases&perpage=50
Or maybe check in here
http://www.mangago.me/tag/Car%20accident/
Sorry I'm not helping much :(
The boy and girl are childhood friends the girl falls for someone and the guy also likes guys and he gets hit by a car on his birthday and the the childhood friends end up together help plzzzz I also remember a few other scenes like when he invited that guy to play video games at his house