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Video recording of Rear end collision - Why not?

Jan 18, 2021
7
2
Los Angeles
In November I was the vicim of a hit and run rear end collision causing significant damage to my 2019 Model 3. The driver sped off turning right before I could identify him through a license number, etc.

It was a block from my house and I was able to creep home. I was completely covered although it took two and a half months for the repairs.

I had Sentry Mode enabled but it did not record that information. Why is this? Why not? It seems silly that in a rear end collision of this magnitude that it was not recorded. Why is there no method to engage all the cameras for continuous recording while driving; my large capacity flash drive was operational. It certainly did not record this event. In my case, it would have been extremely beneficial.
 

ViperDoc

Roadster 1305
Jun 24, 2011
420
210
Vermont
IT might be that Sentry is only operational when you are parked. However, when you need to record something while driving, you just tap the camera icon on the screen.
 
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JulienW

Active Member
Jul 7, 2018
2,589
2,835
Atlanta
If you were driving that would be Dashcam. As ViperDoc stated Sentry Mode is for a parked car and part of the alarm system. In Dashcam you MUST save the incident by touching the Dashcam icon or by (optionally if enabled) honking the horn. Page 76 of the manual.

Screen Shot 2021-01-19 at 5.38.54 AM.png
 
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mrau

Authorized Driver
Supporting Member
Nov 12, 2018
442
840
Mid-Michigan
The Dashcam automatically saves the most recent 60 minutes that the car has been awake (driving or parked). Anything older is auto deleted. As stated, you can tap the icon to Save the last 10 minutes or honk the horn (be sure to turn horn option on) and it will not be auto deleted. If something happened in the last hour you want to save, but missed the 10 minute window, you can stop the Dashcam from recording (press & hold icon until it pulses) and then pull your drive out of USB to make sure it is not deleted.

Of course you have to remember to do these things, and they are easy to forget during stressful events like an accident.
 

de Vere

Member
Feb 13, 2018
12
7
Los Angeles
To the OP's original question: He seems well aware of the Dashcam function. His query is rather why it is not possible to engage recording of the side and rear cameras as well while moving/driving.

Add my voice to folks who would prefer to see a toggle enable-recording of all cameras during driving. Any way to accomplish this at present?
 
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JulienW

Active Member
Jul 7, 2018
2,589
2,835
Atlanta
To the OP's original question: He seems well aware of the Dashcam function. His query is rather why it is not possible to engage recording of the side and rear cameras as well while moving/driving.

Add my voice to folks who would prefer to see a toggle enable-recording of all cameras during driving. Any way to accomplish this at present?
There are NO cameras called Side cameras. There are Repeater and B-Pillar cameras on the side of the car and the Repeaters are recorded as well as Rear and standard Front.

However where are you interpreting that the OP has a Dashcam recording missing the Repeater and Rear cameras (only the standard Front camera???) or wanted the B-Pillar view? The Op says he/she was rear ended and the there is NO recording. The OP wants the license plate number, not another view which in Calf would have been recorded by the Rear camera and maybe the Repeaters.

Of course the OP posted once and is now MIA with no follow up.
 
Jan 18, 2021
7
2
Los Angeles
There are NO cameras called Side cameras. There are Repeater and B-Pillar cameras on the side of the car and the Repeaters are recorded as well as Rear and standard Front.

However where are you interpreting that the OP has a Dashcam recording missing the Repeater and Rear cameras (only the standard Front camera???) or wanted the B-Pillar view? The Op says he/she was rear ended and the there is NO recording. The OP wants the license plate number, not another view which in Calf would have been recorded by the Rear camera and maybe the Repeaters.

Of course the OP posted once and is now MIA with no follow up.


Shortly after the collision, I removed the USB memory stick and watched it on my desktop computer. There was nothing recorded during the rear end hit and run collision. It had recorded over views about an hour before and about a half hour later. I was standing at a green light waiting for a chance to turn down my street. Then the collision occurred. I expected that there would be a recording of that.
 

JulienW

Active Member
Jul 7, 2018
2,589
2,835
Atlanta
Shortly after the collision, I removed the USB memory stick and watched it on my desktop computer. There was nothing recorded during the rear end hit and run collision. It had recorded over views about an hour before and about a half hour later. I was standing at a green light waiting for a chance to turn down my street. Then the collision occurred. I expected that there would be a recording of that.
As stated you MUST save it before you remove the drive. Sorry but that is the way it works and what Tesla says to do. Maybe Tesla will modify it so it saves automatically when a certain G-Force load is encountered but that will not help you now.

If you still have the drive out the data is likely ON the drive and just the file flags are erased. So you may be able to recover part of all of the data using data recovery tools.
 
Jan 18, 2021
7
2
Los Angeles
As stated you MUST save it before you remove the drive. Sorry but that is the way it works and what Tesla says to do. Maybe Tesla will modify it so it saves automatically when a certain G-Force load is encountered but that will not help you now.

If you still have the drive out the data is likely ON the drive and just the file flags are erased. So you may be able to recover part of all of the data using data recovery tools.
As stated you MUST save it before you remove the drive. Sorry but that is the way it works and what Tesla says to do. Maybe Tesla will modify it so it saves automatically when a certain G-Force load is encountered but that will not help you now.

If you still have the drive out the data is likely ON the drive and just the file flags are erased. So you may be able to recover part of all of the data using data recovery tools.

I did send it to a data recovery IT person and they were unable to recover any helpful data. Since you have mentioned the file flag erasure possibility, I'll ask them to re-check the drive.

I've learned the hard way. Thanks for the reminder. I hope your suggestion about G-Force auto save might reach the tech people at Tesla.
 

drtimhill

Active Member
Apr 25, 2019
1,953
2,452
Seattle
To the OP's original question: He seems well aware of the Dashcam function. His query is rather why it is not possible to engage recording of the side and rear cameras as well while moving/driving.

Add my voice to folks who would prefer to see a toggle enable-recording of all cameras during driving. Any way to accomplish this at present?

If Dashcam is enabled then all the cameras are recording all the time while you are driving. However, these recordings are on a 60 minutes loop, so only the last 60 minutes is accessible. When you tap the dashcam icon (or honk if enabled), the last 10 minutes of video are moved to a permanent location for later playback (and are not deleted until you manually do so).
 
Jan 18, 2021
7
2
Los Angeles
If Dashcam is enabled then all the cameras are recording all the time while you are driving. However, these recordings are on a 60 minutes loop, so only the last 60 minutes is accessible. When you tap the dashcam icon (or honk if enabled), the last 10 minutes of video are moved to a permanent location for later playback (and are not deleted until you manually do so).


Thank you for the information.
 

JulienW

Active Member
Jul 7, 2018
2,589
2,835
Atlanta
Just a slight correction. We actually have 9 cameras with 8 being external and 4 used in recording. Here is a list:

  • Interior (located in rear view mirror)
  • Front Wide Angle
  • Front Telephoto
  • Front Normal (used for recording)
  • Rear (used for recording)
  • B-Pillars left and right
  • Repeaters (aka: fender) left and right (used for recording)
 
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CyberGus

Not Just a Member
May 5, 2020
1,017
2,225
Austin, TX
Computers store information using data and metadata. Think of a postal letter: the address on the envelope is the meta-data, but the letter inside is the data.

When writing continuously to a file, such as in the Dashcam, the data is committed to the drive almost immediately (caching improves performance but makes the writing lag behind reality slightly). However, the metadata that describes how to find the contents of the file are usually not written until the file is closed (this varies with the OS).

So, the dashcam footage data should be on the drive, minus whatever was lost from the cache when the drive was removed. But without the metadata, it will be difficult to piece the blocks back together. And if the drive was subsequently used, the misplaced data could be overwritten since it is not marked as being in-use.

For exFAT filesystems, the block size is 32K, meaning that a 32G flashdrive has one million blocks. For ext4 filesystems, the blocks are only 4K. The blocks of any given file are probably continuous or only in a few segments, but this is not guaranteed, and the file fragmentation gets worse as the drive is used more.

Theoretically, the original file data can be recovered, but reconstructing the pieces could prove to be a daunting puzzle.
 
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Jan 18, 2021
7
2
Los Angeles
In November I was the vicim of a hit and run rear end collision causing significant damage to my 2019 Model 3. The driver sped off turning right before I could identify him through a license number, etc.

It was a block from my house and I was able to creep home. I was completely covered although it took two and a half months for the repairs.

I had Sentry Mode enabled but it did not record that information. Why is this? Why not? It seems silly that in a rear end collision of this magnitude that it was not recorded. Why is there no method to engage all the cameras for continuous recording while driving; my large capacity flash drive was operational. It certainly did not record this event. In my case, it would have been extremely beneficial.
Computers store information using data and metadata. Think of a postal letter: the address on the envelope is the meta-data, but the letter inside is the data.

When writing continuously to a file, such as in the Dashcam, the data is committed to the drive almost immediately (caching improves performance but makes the writing lag behind reality slightly). However, the metadata that describes how to find the contents of the file are usually not written until the file is closed (this varies with the OS).

So, the dashcam footage data should be on the drive, minus whatever was lost from the cache when the drive was removed. But without the metadata, it will be difficult to piece the blocks back together. And if the drive was subsequently used, the misplaced data could be overwritten since it is not marked as being in-use.

For exFAT filesystems, the block size is 32K, meaning that a 32G flashdrive has one million blocks. For ext4 filesystems, the blocks are only 4K. The blocks of any given file are probably continuous or only in a few segments, but this is not guaranteed, and the file fragmentation gets worse as the drive is used more.

Theoretically, the original file data can be recovered, but reconstructing the pieces could prove to be a daunting puzzle.

Thank you...and everyone else who has replied to my questions about the dash cam and the functionality of activating the horn and icon on the screen to save the last recordings.

This Forum is incredibly informative and detailed and obviously actively monitored by Tesla owners. I can't thank everyone enough for your help.

I hope that the Tesla folks will consider an automatic activation of the recording in the event of an accident when any owner would want the recording and perhaps be too traumatized to think clearly about remembering to reach for the dash icon or beep the horn.

Thanks again. Much appreciated.
 
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Jan 18, 2021
7
2
Los Angeles
Just a slight correction. We actually have 9 cameras with 8 being external and 4 used in recording. Here is a list:

  • Interior (located in rear view mirror)
  • Front Wide Angle
  • Front Telephoto
  • Front Normal (used for recording)
  • Rear (used for recording)
  • B-Pillars left and right
  • Repeaters (aka: fender) left and right (used for recording)
It would be sensational to have the relevant camera activated in the event of a collision.
 
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Broccoli2

Member
May 17, 2019
26
27
Santa Clarita CA
I have pulled my flash drive out of my car, without honking or taping the icon and at least the list 60 min in there. If you honk or tap the icon it moves recent files to a separate folder. Is you dash cam turned on. I would think it is not.
 
Jan 18, 2021
7
2
Los Angeles
I have pulled my flash drive out of my car, without honking or taping the icon and at least the list 60 min in there. If you honk or tap the icon it moves recent files to a separate folder. Is you dash cam turned on. I would think it is not.

I have had success in reading/viewing videos. However, it just didn't record the back view at the time of the accident. I will be diligent in the future to either tap the icon or activate the horn. I appreciate your observations. Thank you.;
 

dskillz

Member
Dec 24, 2019
118
94
Los Angeles
I have had success in reading/viewing videos. However, it just didn't record the back view at the time of the accident. I will be diligent in the future to either tap the icon or activate the horn. I appreciate your observations. Thank you.;
I was in an accident this past November where a 18 wheeler side swiped my 2020 Model 3 and the Dashcam failed to record the accident too. I was in such shock when it happened I also failed to honk the horn or hit save on the screen. I just got my car back today!!! It was out of commission for 56 days.
 

Donuts

Member
Oct 11, 2020
31
10
Canada
Same problem on and off dash cam and viewer. 2021 with Tesla USB stick. Today someone reversed into me and of course nothing was recorded. I hit the horn before he actually made contact and it also didn’t trigger dash cam. Why is this so hard to get right. Even updated the software 2 days ago…. Brutal
 

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