Witnesses told 10/11 the accident happened around 12:05 just before the parade in Aurora was supposed to start.
The witness said the leading police escort to start the parade was approaching the intersection of M and 7th Streets, when an older woman driving a car tried to bolt through the stop sign at the intersection.
The person said the driver lost control of the car and crashed into the NW corner of the intersection people who were sitting under a tree and also hitting the tree.
A total of five people were sitting under the tree, but only four were hurt.
A family member and friend said Roger Christenson of Aurora, Sherry Christenson of O'Neill and Marsha Akerson of Aurora were all taken to the Aurora Memorial Hospital by ambulance.
Conditions for the Christenson's were not known at the time, the family member/friend said Akerson was reported to have a broken leg.
A toddler was the fourth person taken to the hospital. Family members took the child for precautionary reasons.
We have a reporter in Aurora and will continue to bring you more information as it becomes available.