US citizen Anne Sacoolas, 45, has been sentenced at the Central Criminal Court of England and Wales, to eight months in prison suspended for 12 months for causing the death of motorcyclist Harry Dunn.
The mother of Mr Dunn broke down in court as her teenage son's killer avoided jail after a three-year fight for justice.
Sacoolas, 45, declined to come to the Old Bailey in person for causing the 19-year-old’s death by careless driving.
Earlier, Mr Dunn’s mother Charlotte Charles had said she was left "absolutely fuming" on learning the US government had advised her not to travel to the UK to face justice, making the sentence effectively unenforceable.
Speaking in a packed Court One of the Old Bailey, Mrs Charles wept as she said: "Harry just disappeared out of my life that night, shattering my existence forever.
"His passing haunts me every minute of every day and I’m not sure how I’m ever going to get over it."
"I made a promise to Harry in the hospital that we would get him justice and a mother never breaks a promise to her son."
In her sentencing, Mrs Justice Cheema-Grubb paid tribute to the Dunn family.
She told Sacoolas: "There is no doubt that the calm and dignified persistence of these parents and family of that young man has led through three years of heartbreak and effort to your appearance before this court and acknowledge your guilt."
The judge said Mr Dunn’s death was the "highest degree of harm" but added: "I bear in mind this was a short period of driving and you were not familiar with English roads.
"I accept you feel genuine remorse."