The incident occurred at Packer Avenue and South 7th Street just before 9 p.m.
According to police, the driver of a 2004 silver Toyota experienced a medical emergency while driving in the area.
The vehicle then collided with four pedestrians who were leaving a nearby carnival.
Medics transported the driver of the Toyota to Presbyterian Hospital for treatment.
The four pedestrians, three adults and a three-year-old child, were transported to Jefferson Hospital for varying injuries, but all remain in stable condition.
Police continue to investigate.