The victim, 23-year-old Joshua Spender, died after being hit by Bratton's van as he crossed the road at a pedestrian crossing on Macon Way in Crewe.
Bratton fled the scene and Mr Spender was taken to hospital after the incident, which took place at 5.30pm on November 5 last year, but he died from his injuries a short time later.
Now Crewe & Nantwich Conservative MP, Dr Kieran Mullan, has written to the Attorney General to ask for the sentence to be reviewed.
Dr Mullan said he had met with members of Mr Spender's family who he said "know nothing can bring him back", but "want to see the man responsible for his death suitably punished".
Bratton's sentence was reduced by the court from seven years to six years and three months as credit for his guilty plea.
In his letter Dr Mullan said he wanted the case referred to the court of appeal for review.
Writing on Facebook he said that he believed the sentence in cases of this nature was too low.
He said: "I know many people beyond just his family were deeply upset about the killing of local man Joshua Spender. The loss for Joshua's family has of course been devastating. I didn't know Josh but we can all imagine what it would be like to suffer the loss of a family member in this way.
"There is a petition locally asking for the sentence for his killer to be reviewed. After consulting with Joshua's family I have written to the Attorney General asking her to review the sentence to see if it can be referred to the Court of Appeal as unduly lenient.
"I have been honest with Joshua's family that I think sadly we may not get the answer we would like. Our courts act on precedence, what sentence is normally given, and in my opinion the precedent in cases like this and many others is too low."
Chester Crown Court, where Bratton was sentenced, had heard that the traffic lights had changed to red as the driver approached the crossing.
The judge was told he had driven through the red light five seconds after they had changed.
People in a van travelling in the other direction said they believed he was speeding up, rather than slowing down, as Joshua had stepped off the pavement.