In late 2018, Tesla upgraded the Model 3 software to allow drivers to start recording and saving video from the vehicle’s front-facing camera. The quality wasn’t great, and the field of view was rather narrow, but it effectively gave driver’s a free dashcam.
The software has been updated over time, and now (2019), drivers can not only record footage from the front-facing camera, but also from the side-facing cameras.
As of March 2019 and software update v9, Tesla’s recommendation from their website was:
Dashcam. You can now record and store video footage captured by your car’s forward-facing camera onto a USB flash drive. To record: Configure your USB flash drive by formatting in the ‘FAT32’ (Windows) / ‘MS-DOS (FAT)’ (Mac) file architecture and add a base-level folder in the flash drive called ‘TeslaCam’. Insert configured USB flash drive into either of the USB ports in the front row. When properly configured, the Dashcam icon will be displayed in the status bar with a red dot indicating that it is recording.
Note, the USB must be plugged in while driving to record. Tap the icon to save a 10-minute video clip or press and hold to pause recording. Recordings not downloaded after an hour will be deleted. Be sure you have sufficient space on your flash drive to allow for saving (each minute of video recorded uses approximately 30 MB; the 1-hour circular buffer requires ~1.8 GB of free space). Dashcam is only available for Model S and Model X cars manufactured after August 2017, and all Model 3 cars.
While many Tesla owners are fixated on the size of their storage media, I’m more interested in the durability. These cameras are going to be writing constantly to the storage media, and that eventually takes a toll on the media. Instead of buying a large USB “thumbdrive” or “jumpdrive,” you might consider buying a high-endurance microSD card and using a USB reader. Alternatively, if you can find a high-endurance USB drive, please mention it in the comments.