Dashcam

A dashcam, short for "dashboard camera" is a video camera inside a car or other road vehicle that records driving and sometimes what's happening inside the car (useful for taxi drivers) they normally suction onto the cars windscreen and are powered from the car, some have an extra camera that can be put in the rear windscreen to record what's happening behind.
Dashcams are useful because video doesn't lie, it can for instance be used to see who caused a crash, important because some people deliberately crash into innocent peoples cars and blame them for causing the crash, so they can claim it on their insurance, dashcam footage can settle this, it's also important in other accident investigations, even ones that you weren't involved in, they have also recorded meteors and even airplane crashes.
Early kinds of dashcam were used by police to film their patrols, but ones made for the average joe have become increasingly avalible in the last 10 or so years.
Dashcams are very popular in Russia.