Mia Wort, 18, from Southampton, was a passenger in a Ford Focus when it collided with an Audi A3 on the A27 Kanes Hill in Bursledon in the early hours on Saturday.
Ms Wort, of Honeysuckle Road, was taken to hospital where she died from her injuries.
Her family said she was a “loving and caring daughter, sister and mother”.
In a statement, they said: “Words cannot express the heartache we all feel by having Mia taken away from us so suddenly and so unnecessarily”
We watched with pride as she took her first steps as a new parent with her family by her side. She was looking forward to a long future with her daughter; this has now been taken away from her and leaves a void that can never be filled
The family of Mia Wort
“As a family we will pull together to ensure that her memory never fades away and that her daughter will know her mother.”
A 36-year-old man has been arrested on suspicion of:
Causing death by dangerous driving
Causing death by careless driving
Causing death by driving whilst disqualified
Aggravated vehicle taking
Driving whilst over the prescribed limit
Failing to stop following a road traffic collision
He has been released under investigation while inquiries continue.