Ms Ford said the judge made the "wrong decision".
The mother of a woman killed by a driver who crashed into her car after using her phone, said the sentence given was not long enough.
Phillipa Curtis, 21, from Suffolk, had been using her phone before she hit the back of Victoria McBryde's stationary car at 70mph on the A40 in Oxfordshire.
She was jailed for 21 months after being found guilty of causing death by dangerous driving.
Jen Ford, Ms McBryde's mother, said the judge's decision was "wrong".
Ms McBryde, 24, from Horton in Northamptonshire, was dealing with a burst tyre when her car was struck in November 2007. She suffered fatal brain injuries.
Curtis, of Bury St Edmunds, was also given a three-year driving ban.
Judge Julian Hall said it had been "folly and madness" to use a phone while driving and it had been "disastrous" for Curtis, Ms McBryde and her family.
But Ms Ford said she did not think the sentence was enough of a deterrent.
"My Tori was horribly killed by Philippa Curtis because she chose to use her mobile phone while driving in pitch black and at 70mph," she said.
"Tori was my shining star, my truly beautiful baby and my friend.
"I would like to say that Ms Curtis's sentence is the judges decision - though I feel it was the wrong one.
Ms Ford said everyone who used their phone while they were driving made a conscious decision to break the law.
"My family is shattered irreparably, my sentence is life-long sadness."
When sentencing, Judge Hall said he hoped the case would send out a warning to other drivers not to use their phones when behind the wheel.