A 24-year-old man is also in a critical condition and a one-year-girl suffered minor injuries following the collision in Dartford on Sunday evening.
Kent Police said it was called to reports of a collision involving two grey Ford Rangers on New Barn Road at around 9.30pm.
The three people who were hurt were from the same vehicle, the force added.
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Officers arrested a 27-year-old man from Darenth and a 53-year-old man from Swanley in connection with the incident on Monday. Both remain in custody.
Anyone with information on the crash, including CCTV or dashcam footage, is asked to contact police.
