We've all done it or had it done to us: You're trying to make a left turn across two lanes of oncoming traffic and the driver in the lane closest to you waves you though.
It's supposed to be a courteous gesture and you'd be rude not to go. But those good intentions can be costly; the price could be a life.
Backed up traffic can be frustrating, but Midwest nice usually prevails. And waving someone to turn left in front of you is just par for the course.
"Everybody just wants to be nice. They stop and it's a kind gesture to let somebody go but people don't realize it's really, really dangerous," mother Pam Sorensen said.
Sorensen's teenage daughter was waved across two lanes of traffic by another driver.
"And we've told her many, many, many times, you don't go through because you can't see the far lane and you can't see what's coming. But she felt the pressure of that person waving and she didn't want to make them angry," Sorensen said.
It was a bad decision.
"Luckily, she got far enough through that it hit on the back corner of her car and not right on the passenger side because she did have a friend in the car with her," Sorensen said.
Mindy Moore was involved in the same kind of crash, but she was driving in the far lane.
"He turned right in front of me. I jammed on my brakes and did what I could, but we still had a pretty good collision," Moore said.
In both Moore's and Sorensen's crashes no one was seriously hurt, but the cars were totaled.
"Those are some of the worst collisions you might have. Even though you only have a 30 mile-an-hour collision, you still have a straight T-bone," Traffic Officer Jeff Gillespie said.
"They have a term for it at our insurance company. They call it the wave of death," Moore said.
And people have died. In October of 2012, 75-year-old Jim Heezen was killed when the car he was in, driven by a friend, was hit as it crossed two lanes of traffic. They were waved across by another driver on East 10 Street.
"I understand the last thing he said to Harlan was, 'Gun it.' He saw this Hummer coming at him. But that was it," Nancy Johnson said.
Heezen was Johnson's only living sibling. She says Heezen's family continues to struggle with their loss, including his grandnephew, who was crazy about him.
"It's the hardest on him and me because we were the last ones. Now I'm the last one," Johnson said.
In the case of Heezen's deadly crash and most like it, the driver who waved the other car through doesn't stick around.
"Even though criminally, they may not have been responsible, it sure still would weigh on your conscience I would think,” Gillespie said.
In both Sorensen's and Moore's cases, the waver kept on going.
"There's no way he couldn't have heard or seen that accident. It would have happened right in front of him," Moore said.
Even if they're waved through, the driver turning left is always at fault in these crashes and will get a ticket for turning in front of oncoming traffic. Police say if you're driving in the far lane and you come up to traffic that has come to a standstill, to your left, be mindful of a gap because there could be a car trying to cut across right in front of you.
People who've been involved in these crashes no longer consider the wave from other drivers polite.
"Ironically, two days later, same intersection, I was waved through. People wanted me to drive through. They were trying to leave space and I just put my hand up and said, 'No thank you.' Just because it had just happened to me," Moore said.
"And I just shake my head and do this for them to continue and you can tell they are very annoyed you are rejecting their kind gesture. But I know now, it's really just dangerous," Sorensen said.
After her family's loss, Johnson just hopes that the message gets out to all drivers not to wave and to never risk making that turn if someone does.
"Because that split second changed our lives forever," Johnson said.
The most common crash in Sioux Falls is a rear-end collision, but police say this kind of accident could be a close second.