A friend installed a dash cam after a minor collision at a Kathmandu roundabout left him arguing over fault with no way to prove his side. Six months later he needed it again, reached for the footage, and found the exact minutes he needed had already been recorded over. The camera had been running the whole time. It just hadn't been told to keep the one clip that actually mattered.
Why Loop Recording Is a Feature and a Trap
Dash cams record continuously and reuse the same storage card by overwriting the oldest footage once it fills up, which is exactly what lets a small SD card run for weeks without needing attention. That same behavior means ordinary footage, including the minutes right after an incident, gets recorded over automatically unless something tells the camera not to touch it. The recording itself was never the weak point. Not protecting it in time is.
What Actually Protects a Clip
Most dash cams include a G-sensor that detects sudden impact or hard braking and automatically locks the current clip so loop recording can't overwrite it, along with a manual lock button for anything the sensor misses, a near-miss or a dispute that didn't involve an actual collision. Relying on the G-sensor alone is a gamble: sensitivity settings vary, and a glancing bump or a hard pothole doesn't always trigger it the way a full-speed collision would.
Why the Footage Itself Holds Up
Dash cam footage carries a timestamp and, on many models, GPS and speed data embedded directly in the file, details that are far harder to dispute than a verbal account of what happened. That evidentiary weight is exactly why footage-backed claims tend to move faster and resolve more favorably in insurance disputes generally, since there's an objective record instead of two conflicting stories about who had the right of way at the roundabout.
The Honest Verdict
A dash cam is worth having for exactly the situation my friend was in, a Kathmandu intersection with no witnesses and no way to prove what happened. But the camera only helps if you know to act fast afterward: press the lock button immediately after any incident, don't assume the G-sensor caught it, and pull the footage off the card the same day rather than trusting it to sit safely on a card that's designed to keep recording over itself.
