Maisie Godden-Hall was cycling to school as normal last November when she was hit by a car in London Road in Waterlooville.
The 12-year-old braked suddenly and flew head-first over her handlebars at a junction, landing in front of a vehicle.
She was run over and left with a crushed pelvis, lost seven teeth and had to undergo surgery to stitch up her face.
Now, just over a year after the ordeal, she is calling for cycle helmets to be made mandatory under law – after doctors said she would have died if she was not wearing one at the time.
The Oaklands Catholic School pupil, from Widley, said: ‘While some people don’t like wearing helmets, they really can save a life.
‘It’s not a nice thing to think about but if I wasn’t wearing mine on the day of the accident I might not be here any more.
‘They’re not that expensive and you never know when you are going to need one, like I did.
‘I think it should be the law to have to wear a helmet.’
After emergency services rushed to Maisie’s accident on November 3, 2016, the then 10-year-old was flown to Southampton General Hospital in an air ambulance.
She was discharged a month later in a wheelchair, which she had to use to allow herself to recover.
As her daughter now embarks on a bid to make helmets mandatory, Maisie’s mother, Jane, says she ‘couldn’t be prouder’.
The 50-year-old said: ‘What Maisie is doing is turning a horrific situation into something positive.
‘I remember walking into the hospital’s intensive care unit and seeing what had happened to her after the accident.
‘No parent should have to see what I saw or get the phone call I received after it happened.
‘The fact Maisie is now pushing to make a change in the law is amazing. As her mum I definitely couldn’t be prouder.’
As well as campaigning, the youngster is currently working with Hampshire Constabulary to create a series of road safety videos.
And while wearing a helmet is still only encouraged but not enforced, the 12-year-old has a clear message to cyclists who steer clear of the kit.
She said: ‘Before my accident, it was just a normal day – I didn’t know I was going to need one.
‘But I’m glad I put one on, because things could have been a lot worse.
‘If you want to be safe, you should always wear your helmet.’