Tractors
You don't hear of them being involved of high speed crashes
Some more tips:
Make sure the car bonnet or dash (near windscreen) is partly showing at bottom of image - this can be used to calculate distance, mainly for major crash when police use more resources into investigation.
The car radio playing can be used to ID the correct time & day - again mainly for major crash but also if other driver gives wrong time to benefit themself.
Get a new dashcam every 2 or 3 years for reliable functioning and also technology/features improvement. I'm on my 4th camera in about 7 years.
Having a single dashcam may not show action towards the rear but it shows you were driving correctly at the time.
The dashcam is like having a airplane blackboard in your car. And when other driver tells pork pies, the video is great evidence. Do you realise all the at fault driver has to say is he was not even there, then you or police must prove it. How much resource are police likely to use investigating a minor crash?