http://www.techradar.com/news/the-10-best-dash-cams-you-can-buy-right-now

Where the now-ubiquitous action camera was born out of a desire to capture totally awesome adventures for social media posterity, the slightly less glamorous dashcam was designed to make insurance claims easier, or provide essential evidence should an incident on the road require legal attention.

Unfortunately, insurance companies across the globe have reported an increase in 'cash for crash' scams, where a fraudulent motorist will deliberately slam on their brakes to make the car behind run into the back of them.