Three cars were completely totaled when a truck collided with a tractor-trailer ... and the insane accident was caught on video.

Another semi was waiting to turn at the intersection of W Avenue and Highway 3 in Iowa on Monday, and you can see the tractor-trailer coming down the road on the dashcam.

As it approaches the intersection, a Dodge Ram comes into frame from the road on the right, barreling towards the stop sign and blowing right through it.

As you can see ... the truck completely cuts off the semi, smashing the front of the cab and getting T-boned in the process.

According to the Fayette County Sheriff's Office, the trucks collided with a Chevy Impala sitting at a stop sign off camera, noting all three vehicles are "a total loss."

The truck's driver, his passenger, and the semi's driver were all taken to Community Memorial Hospital in Sumner, the sheriff's office says.

The extent of any injuries is unclear, and the authorities didn't mention how the sedan's driver is doing.

The crash investigation is ongoing.