Homicide detectives and collision reconstruction officers are initiating the investigation, Allegheny County Police say.
The truck driver told police he knew he hit something but had no idea it was a person until he stopped and got out of his vehicle.
Witnesses told police they heard the backup warning sound from the truck.
This happened just around 11 a.m. and those going about their business shocked to learn what happened.
Katelyn Craig, a hair stylist working in the salon across the street watched the scene unfold from their window: “It’s a busy window, we get to see a lot but this is not necessarily what you want to see.”
Police are investigating. The medical examiner has not released the victim’s name yet.