Taylor McDonnell is accused of knocking down grandparents Denis and Joyce Drew as they took an evening stroll together in a quiet village
A hairdresser made "four or five phone calls" on her mobile phone while driving in her slippers before ploughing into an elderly couple and killing them, a court heard.
Taylor McDonnell, 21, knocked down grandparents Denis and Joyce Drew, both 86, as they took an evening stroll together in a quiet village.
A court heard McDonnell spent 18 minutes of her 20 minute drive making a series of phone calls as she drove to see her boyfriend, when she hit Mr and Mrs Drew.
Retired RAF airman Denis and teacher Joyce - married for 54 years - died after being hit by the blue Toyota Aygo with McDonnell behind the wheel.
McDonnell, of Caerwent, Monmouthshire, denies two counts of causing death bydangerous driving.
Prosecutor Lucy Crowther said: "She was grossly distracted by her telephone.
"She wasn't paying proper attention to her driving - which ultimately caused the deaths of two elderly people - because a telephone call was far more important."
Newport Crown Court was told Mr and Mrs Drew had been walking the short distance home after visiting a friend in the quiet village of Ponthir, near Caerleon, South Wales.
They both used walking sticks and were seen walking slowly together on November 13, 2013.
They were side by side as they walked across the quiet 30mph road outside a well-lit local pub.
"They had very nearly finished their crossing when they were hit by the blue Toyota Aygo being driven at around 30mph by the defendant," Miss Crowther told the court.
"Mrs Drew was flung onto the bonnet and windscreen and part of her body struck the side of the car before she was thrown onto the verge.
"Mr Drew was hit by the car and run over.
"His legs were trapped underneath the car and he was dragged along the road for more than 16 metres until the car was stopped.
"The defendant didn't brake her car until she hit Mr and Mrs Drew.
"She didn't take any action to avoid the couple.
"She stopped her car and ran into the nearby public house for help."
The court heard McDonnell thought she had hit a woman on her own and didn't realise Mr Drew was stuck under her car.
Drinkers in the Star Inn recalled her running hysterically into the bar and screaming for help while clutching her iPhone in her hand.
The court heard she said: "I was driving along the road, I didn't even see her until she hit my windscreen."
Family and friends of the elderly couple wept as they listened to the heroic efforts of other motorists to comfort the stricken pair as they lay seriously injured on ground.
One driver discovered Mrs Drew lying on the verge with her "clothes in disarray" and covered her with a fluorescent jacket.
Miss Crowther said: "The gentleman gave her basic first aid and could tell she was still alive.
"He stayed with her and talked to her and stroked her hair and held her hand.
"He comforted her just to do what he could for someone clearly in extremis.
"As he did that he heard a groaning and could see Mr Drew was trapped beneath the car."
The court was told Mr Drew was able to speak to police officers and paramedics fighting to free him. "He spent all the time asking about his wife," Miss Crowther said.
Mrs Drew died of "massive injuries" in the Royal Gwent Hospital just a few hours later.
Mr Drew was too weak to undergo surgery to treat the multiple fractures, cuts and deep bruising he suffered, and he died in the same hospital six days later.
Miss Crowther said McDonnell admitted speaking on her telephone but said she had been using the loudspeaker function when the crash occured.
But she said the young driver insisted she had been "driving carefully and paying attention to the road" and there was nothing she could have done to avoid the collision.
Miss Crowther said: "She said in essence she thought Mrs Drew had run out into the road ahead of her.
"We say her driving fell far below the standard of a reasonable and competent driver.
"Had she been paying attention to the road the least she could have done is slow down and try to avoid them, or have done something.
"But if you are on the telephone it makes it very hard to look out of the windscreen and see anything."
The trial continues.