can a drive cam pick up another cars speedometer

[SanMaximus]

No, a standard dash cam cannot reliably pick up the speedometer of another car. The primary reason is technical: dash cams use wide-angle lenses to capture a broad view of the road, which makes small details like the numbers on a distant speedometer appear blurry and pixelated. Even with high-resolution cameras, factors like distance, relative speed, glare on the other car's windshield, and low light conditions make it nearly impossible to get a clear, readable image.

The intended purpose of a dash cam is to record events for insurance and legal evidence, focusing on vehicle actions like lane changes, signal use, and overall traffic flow. Capturing a specific, small instrument panel in another moving vehicle is beyond its design scope. For a reading to be legally admissible, it would need to be unambiguous, which a dash cam video almost certainly would not provide.

If you need to verify another driver's speed for legal reasons, law enforcement uses calibrated radar or LIDAR guns, which are designed for this specific task and provide court-admissible evidence. Relying on a dash cam for this purpose will lead to frustration and unusable footage.

Factor	Why It Prevents Clear Speedometer Capture
Lens Type	Wide-angle lens prioritizes field of view over zooming on small details.
Resolution	Even 4K resolution lacks sufficient pixel density on a small, distant object.
Distance	The farther the other car, the smaller and less distinct its speedometer becomes.
Motion Blur	Both cars moving creates vibration and blur, smearing small numbers.
Windshield Glare	Reflections and tinting on the other car's windshield often obscure the dashboard.
Frame Rate	Standard 30 fps may not capture the exact moment a needle passes a number.
Angle	The viewing angle to see the speedometer clearly is rarely achieved in traffic.

[StFrancisco]

Not a chance. I've tried to zoom in on my own dash cam footage to read a license plate just a car length away, and it's often a blurry mess. Trying to see the tiny numbers on a speedometer inside another car through two windshields? You'd have to be practically bumper-to-bumper, and even then, the angle is usually wrong. It's just not what these cameras are built for. They're for showing what happened, not for playing detective on specific details inside other vehicles.

[Gael]

As a tool for evidence, a dash cam's value is in documenting the sequence of events—like who had the right of way. It is not a speed-measuring device. The legal standard for proving a vehicle's speed requires calibration and specific methodology that a consumer dash cam cannot provide. Any attempt to use such footage to report another driver's speed would likely be dismissed due to the lack of clarity and calibration. Your footage is best used to show how a driver was behaving, not to precisely measure their speed.

[Luis]

Think of it like this: your eyes can see a bird in a tree across the street, but you probably can't count the spots on its feathers from that distance. A dash cam is similar. It sees the whole scene, but it doesn't have a powerful zoom to pick out fine details from far away. The technology focuses on capturing a wide area to protect you in an accident. For catching speed, you're better off leaving it to the police with their specialized equipment.

[AshlynLee]

I wish it were that easy! If dash cams could do that, everyone would be reporting speeders left and right. The reality is much less like a spy movie. The camera is focused outwards, and the other car's windshield often has a tinted strip at the top or just reflects the sky. Unless you're tailgating them perfectly in ideal light, the numbers are just a smudge. It's a cool idea, but the physics and optics of the situation just don't work out in practice. Save the camera for what it's good at: proving you weren't at fault in a crash.