The Pioneer ND-DVR100 Dash Cam is a must-have product! It starts recording when it is turned on and will automatically record over the oldest clips. If the built-in G-sensor detects an impact incident (such as a collision while in motion or a bump while parked), that video file is locked and stored in an Event folder so it won't be overwritten. This dash cam records 1080p HD video at 27.5 frames per second plus features a wide aperture lens to provide high-quality recordings and still photos in daylight and low light. The 27.5 frame rate was specifically chosen to accurately capture LED traffic lights, which often operate at 60 Hz—especially helpful in the case of a traffic-signal-related video. In addition to recording video, you can take still pictures with the camera. This is helpful if you need to take detailed photos from outside the vehicle in case of an accident. You'll be glad you have this dash camera onboard!