The car traveling in the correct direction veered to miss the wrong way driver and crashed.
"Wrong way drivers actually do come up quite a bit on their last lesson," said Jeremy Cain, general manager at Crash Course Driver Education Center in Milwaukee.
We showed video of the wrong-way driver to Cain and who said students often ask what to do in this situation.
"What you want to do is pull over and call 911," he said. "Don't try to be that person that tries to flash my lights."
He says scanning ahead in traffic can help you have more time to react and pull over safely.
"The thing you want to remember with wrong way drivers, we don’t know what’s going on with them in the car," said Cain. "We don't know if they're having a health issue, a heart attack or if they're under the influence."
Wauwatosa Fire Department medical units responded to treat two adults and three children all in the car that crashed. Two of the kids were taken to Children's Hospital with pain in their arms, legs and head.
The sheriff's office said the wrong way driver was last seen going south on Burleigh Avenue and has not been found.
Two lanes of traffic were closed for less than an hour to clear the scene.