I have had a dash cam for two years. They are cheap and widely available. Eg. Amazon and eBay.
I have used my recordings with insurance companies twice.
Once when a woman admitted to me at the scene that she was at fault for hitting me. Then several hours later claimed to her insurance company the accident was my fault. I showed her insurance adjuster my dashcam video and they paid me (more than) in full, as well as dumped the lady for filing a false claim. I am pretty sure that is a federal offense as well(?).
The attached video was used to show that I was… going the speed limit, I had no options to change lanes, it was not the fault of the vehicle ahead of me, and that I was not following too closely. It was simply a damage claim. The camera is actually 1080p but this .gif is small an a LOT less clear than the original 60mg file.
If you do not have a dashcam I highly suggest you get one.
BTW… if the accident is your fault, pull out the SD card immediately and swallow it.
EDIT: I guess the video idea didn’t work as planned, but you get the general message here.