SA judge urged to show mercy on mother

A woman who killed her four-year-old daughter in a road crash while on drugs is already a "prisoner in her own mind", a court has been told.

Kylie Anne Hie pleaded guilty to causing death by dangerous driving in relation to the crash in November 2013, when she drove her van into the back of a truck on Adelaide's South Eastern Freeway, killing her daughter Charlotte.

In the District Court on Friday, defence counsel Heather Stokes asked for her client to be given a suspended sentence or home detention considering the emotional trauma she had been through.

"This court can never punish her any more than she punishes herself every day," Ms Stokes said.

But prosecutor Carmen Matteo said both a suspended jail term or a home detention sentence were not appropriate given Hie's prior offences for bad driving and the level of methamphetamine in her system.

She said the woman's driving on the day involved risk taking and was erratic and dangerous.

The 34-year-old was observed to be driving at speed, straddling lanes and squeezing into small gaps in the traffic for some time before the crash.

The taking of an innocent young life must be reflected in the sentence, Ms Matteo said.

In a victim impact statement read to the court, Charlotte's father Aaron Hie said his daughter's life was ended early, "by the negligence of not just any woman, but by her mother".

"This was no car accident. This was a car crash that should not have happened," he said.

Hie sobbed through the reading of the statement but outside court sprayed the media with water as she left.

She will be sentenced in April.