US citizen Anne Sacoolas, who left the UK after a charge of causing death by dangerous driving, returned home under the protection of diplomatic immunity.
An extradition request was later blocked and she has remained on US soil.
In August 2019, while driving on the wrong side of the road, Anne Sacoolas collided with motorcyclist Harry Dunn (19) who later died.
A US judge has now said she must face trial, at least in civil court, and ruled that a lawsuit filed in Virginia by Dunn's family can go forward.
The family are claiming wrongful death.
Judge Ellis has also said the family may pursue a damage claim against Sacoolas's husband, whose car she was driving at the time.