Ask any attorney, the best two ways to protect yourself are 1. ALWAYS remain silent until you speak to your attorney and 2. RECORD EVERYTHING.
Dash cams change the balance in legal battles. Here's how you can easily have one for around $10.00.
Step 1. Buy a simple device to hold your phone on the dash or windshield. I use a grip go. They are $10.00 at Walgreens.
Step 2. Download a Dash Cam app onto your cell phone. (I have tried and reviewed every one of them and can confidently say "Safe Drives" is by far the best.
That's it. You now have a Dash Cam. Its up to you to develop the habit of using it. Show your friends and encourage them to protect themselves as well.