EMBED >More News Videos Bianca Roberson's father speaks following the sentencing of his daughter's killer on December 13, 2018.

EMBED >More News Videos Funeral held for teen killed in road rage shooting. John Rawlins reports during Action News at 4pm on July 7, 2017.

WEST CHESTER, Pa. (WPVI) -- A Pennsylvania man who pleaded guilty to fatally shooting a recent high school graduate in a fit of road rage should spend at least 20 years in prison after an emotional sentencing at which he, the victim's family and even the judge cried.David Desper was sentenced to 20 to 40 years.In a victim impact statement, the father of Bianca Roberson remembered his daughter as being generous and hardworking."My questions for the defendant are simple. Why in God's name did you shoot my daughter? Because she was young? Because she was black? Because she was a girl? Because you wanted to go first on the road? Because you had a bad day?" Rodney Roberson read.There was not a dry eye on the courtroom in the room as Bianca's father struggled to speak through tears about his daughter."All my dreams for Bianca were coming true. Until the day that the defendant murdered my daughter," Roberson's said. "All I have left of Bianca is my memories."Judge Ann Marie Wheatcraft teared up as the father referenced Luther Vandross' song."She had a special song that she said was her song just for me - 'Dancing With My Father' by Luther Vandross. It is a song about a child whose father died, and about how that child is praying for one more dance with her father. I always teased her that it was such a sad song and I planned on living forever anyway,"Michelle Roberson, Bianca's mom, lost her son when he was 22 due to a sudden heart attack. Bianca was her second and last child to die.She said in court, "I never get to hear that word 'mom' again."Michelle Roberson then looked at David Desper and shouted, "I hate you!"Desper pleaded guilty to shooting Bianca, 18, in the head in West Goshen Township last year after they jockeyed for space on a highway merger.Before the sentencing, the defense called Desper "harmless and an almost juvenile 28-year-old" who in his spare time played with cars. They called him "a big kid" and argued that Desper essentially "gave the government the case" because he turned himself in.The defense said Desper was driving home when a car came up on him and startled him. He took the gun and fired it. They said there is no monster or menace.It turned out, Desper's own mother had shared a Facebook post about police looking for the man who murdered Bianca Roberson. She wanted police to find the man she called "the jerk who killed that high school graduate." She'd later learn it was her own son.Wendy Desper said she has love for Bianca's family and prays for her."I'm sorry for what my son did," she said as her son sobbed.When it was the prosecution's turn, they asked for anyone in the room who was affected by the life Bianca Roberson to stand. Two-thirds of the room stood.They said, "Let the record show that none of the defendant's family stood up. I'm surprised as it would seem that they were impacted by Roberson's life, as well."------