Dashcam HD: How to Choose the Right Resolution

Full HD can be enough for general incident context in good conditions. If reading small details at distance matters, 2K or 4K gives you more pixels to work with, although lighting and optics still affect the result.

Not automatically. A well-tuned 2K camera may handle motion or low light better than a weak 4K model, and 4K footage also uses more storage.

HDR can balance very bright and dark areas, which is useful around headlights and street lighting. It cannot recover detail that the sensor never captured.

It depends on resolution, frame rate, codec and the number of channels. Check the manufacturer's supported card capacity and use a high-endurance card designed for continuous recording.