Green’s Dictionary of Slang

1. (US) to crash into (usu. another vehicle) at a right angle, usu. by going over a red light at a junction.

1999		D.C. Murphy ‘Legal Sl. Arm-Off, Leg-Off, Head-Off, And T-Boned’ in Comments on Etymology XXVIII:5 13: Another accident word which is used increasingly in traffic accident reports and industry conversation is ‘T-boned.’ A driver and his auto are said to have been ‘T-boned’ when the vehicle is struck in the side in an intersection by a vehicle travelling at a right angle. ‘He was travelling on Elm Street and got T-boned at 4th.’.
2001		ADS-L 🌐 Two nights ago I was watching the local Portland (OR) TV news and there was one of the usual traffic accident reports. According to the anchor, a car ‘ran a red light and T-boned into a Tri-Met bus.’ [...] I can only infer that she meant the car plowed into the middle of the bus at a right angle so that the two vehicles formed a T.
2004		R.G. Barrett Rosa Marie’s Baby (2013) [ebook] [N]early getting T-boned at Ocean Street by a woman in a 4WD.
2006		C. Hiaasen Nature Girl 155: Nice job, champ [...] You T-boned a garbage truck.
2016		N. Cummins Adventures of the Honey Badger [ebook] Someone had t-boned a cow [...] of Jurassic proportions.
2017		T. Pluck Bad Boy Boogie [ebook] ‘That crazy bitch T-boned my Challenger’.
2021		‘Aidan Truhen’ Seven Demons 244: [The truck] is going to T-bone us like a bear taking out a buffalo calf.

2. in fig. use.

2009

T. Black Gutted 176: A north wind T-boned me at the junction.