This week a North Carolina computer programmer proved he’d discovered a previously not-known-about crash camera function in a Tesla Model S that records events from a collision.
The system uses the camera eye to capture imagery that could be considered evidence for Tesla cars that suffer an air-bag deploying crash, but the function found by a hacker has never been disclosed by either Tesla or federal authorities.
Described to Inverse, the discovered functionality – presumably also equipped in the Model X – was made by Jason Hughes, a Tesla owner and tinkerer, who hacked into a salvaged center display unit he bought to access the car’s last moments on the road.
Hughes tweeted a clip of the Tesla’s last fatal seconds after its driver opted to go through a yellow light at 57 mph and met a white Acura nearly head on as the Acura turned left in front of it.
— Jason Hughes (@wk057) September 13, 2016
The image shows, he said, what appears to be a violation of the Tesla’s right of way by the white Acura, but like memories in a corpse, the image was found in the remains of a ruined car, unbeknownst to anyone.
Hughes’ sleuth work to hack into the system began when he suspected a data dump must occur when an Emergency Braking event occurs.
“I kind of knew what I was looking for, since I had messed with it on my own car,” Hughes said to Inverse. “It’s not too terribly difficult. You have to basically gain root access to the MCU, and such. Tesla’s likely going to make that more difficult. I won’t say it’s simple, but it’s not impossible.”
Out of necessity, the quality of the otherwise clear-enough image is very low, said Hughes.
“It has to send these messages over the CAN bus very quickly to save them from the camera to the MCU [Media Control Unit],” Hughes said to Inverse, “so they have to be dumbed-down resolution so that they can actually make it to the MCU before anything bad happens to it in a crash.”
The data transfer appears to take place when the airbags deploy, and the lag time is still “about 20 seconds.”
In the case of the May death of the driver of an Autopilot equipped Model S in Florida, Hughes surmises the sudden decapitation of that Model S at 74 mph after striking a semi trailer left insufficient time for that event to be recorded.
Not said, but true as well is that car’s driver, Joshua D. Brown, was reported to have never touched the brakes, so no Emergency Braking event occurred. Ultimately however, it’s unclear if the crash cam function might have still worked after the collision and airbag deployment.
As true of the function itself, Tesla has not reported whether this is the case, and neither have federal authorities who have been investigating the crash. Both the National Highway Traffic Safety Administration (NHTSA), and National Transportation Safety Board (NTSB) have been involved after the crash which garnered much public attention, and led to an update for the Autopilot system.
While dash cams are becoming increasingly popular, it appears Tesla for reasons known to itself chose to double up the use of the camera eye used in the Autopilot function for this last bit of forensic evidence, but then keep it to itself.
It’s believed many more benign crashes at least therefore do have evidence stored in them that is not disclosed, and that can even die with the car, assuming it is totaled and salvaged.
As for the unit Hughes found and cracked into, its images might have been useful to know about, had the driver known about it.
“In this case,” Hughes said, “it’s obvious to me that the car making the left turn jumped in front of the Model S. I think that would’ve been useful in their insurance claim.”
This article originally appeared on Hybridcars.com