This is the Yi Camera I'm using. It has loop recording and if in an impact it will save the time before and after the impact and won't write over it.
A lot of the action cameras won't do this.
Current Stable: 2014 XC, Honda PCX 150, 125 SYM Havana.
Born in the deepest jungles of India, I was raised by a friendly bear, until I was kidnapped by a pack of unruly baboons who taught me the finer points of swing jazz, all the while being stalked by an incompetent python and an evil but mis-understood tiger... Ummm, wait a minute, that's the Jungle book, no I was raised just outside of St. Louis, But...in the deepest jungles of a middle class neighborhood .