The boy fell onto the road from the back seat of a white Kia Carnival station wagon in Dayton at 3.50pm yesterday, as reported by the authorities.
Unfortunately, the child succumbed to critical injuries and passed away shortly after the incident, according to a statement from WA police.
Major Crash investigators are currently investigating the scene and are urging any witnesses to come forward by contacting Crime Stoppers at 1800 333 000 or reporting online at www.crimestopperswa.com.au. Dashcam or mobile phone footage of the crash is also being sought.