Dashcam footage has been published to Threads showing three Teslas colliding on a U.S. highway and it is a reminder that not even advanced collision-avoidance systems are infallible.

Footage of the incident was captured by the rear-facing camera of a white car (perhaps a Tesla itself?) showing a red Model 3 pulling out from behind a red Model Y to overtake it. Unfortunately for the driver of this Model 3, a dark grey Model S was traveling in the left-most lane on the highway, U.S. Route 101 in California.

The driver of the grey Model S is unable to brake in time and the sedan ends up rear-ending the Model 3, lifting its rear into the air before it bounces into the concrete barrier in the center of the highway. The Model S then slowly skids into the side of the Model Y.

Read: Pretty Sure The White Tesla Is To Blame For This Crash

The incident has sparked some debate online about whether the Autopilot driver assistance system or Tesla’s Full Self-Driving beta is to blame for the crash. Some suggest that the safety systems of the red Model 3 may have steered it to the left to avoid rear-ending the Model Y.

While this is possible, we think it is more likely that the driver of the Model 3 simply attempted to overtake the Model Y and in the process, forgot to check their mirrors and turned directly into the path of the Model S. There’s also a chance the entire video is fake, but it certainly looks real despite the low quality of the images.

Regardless of what caused the crash, it’s clear that not even the advanced safety systems of the three Tesla models in question make them impervious to crashes and the clip highlights the importance of always remaining attentive while behind the wheel.