Why your dashcam needs to show the speed you were actually doing
Last autumn, we got a support message from a driver in Manchester. He'd been hit at a junction, and the other party claimed he was speeding. His phone had the footage. What he needed was proof of his actual speed at the moment of impact. That's when I realised how many people assume a dashcam app can just conjure this data. It can't, unless it's built in from the start.
The moment you need this data
Insurance disputes rarely turn on opinion. They turn on facts. When you hand over footage to a claims handler or a solicitor, the conversation shifts from 'he said, she said' to 'here's what the camera saw, and here's when it saw it.' A timestamp proves when the incident happened. A GPS speed overlay proves what your vehicle was doing in that moment.
The thing most people don't realise is that video alone isn't enough. A court or claims assessor needs to know you were doing 30 mph in a 30 zone when the other driver ran the light. They need to know it happened at 14:37 on a Tuesday, not whenever the footage was later edited. That's where overlay data becomes critical. It transforms grainy footage into evidence.
Hawk writes both to every clip. The timestamp is baked into the video file itself. The GPS speed comes from your phone's location services, which iOS and Android update dozens of times per second. Together, they tell a story that a still image or a vague description simply cannot.
How GPS speed gets onto your footage
When you mount your phone on the dashboard and tap record, Hawk is running two streams in parallel. The camera is capturing video. Behind the scenes, iOS or Android is feeding location data into the phone's chipset. Hawk reads that data stream and overlays it onto the video in real time. You see your speed, your heading, and a timestamp ticking forward as the footage plays.
The precision depends on your phone's GPS chipset and whether you have a clear view of the sky. A modern iPhone or flagship Android will usually lock to within a few metres and a couple of metres per second of actual speed. That's accurate enough for any dispute. If your phone can't get a GPS lock, the overlay simply shows zero or dashes. Hawk doesn't pretend to have data it doesn't have.
What's less obvious is the privacy angle. You control whether this overlay is enabled in your GDPR profile settings. Some drivers want the full picture; others prefer not to store their location data on the device at all. Both choices are respected. Hawk doesn't force GPS onto anyone.
The manifest that proves it wasn't edited
Footage without integrity is just video. Anyone could splice clips, remove frames, or add text overlays and claim they're original. Courts and insurers know this. That's why Hawk generates a SHA-256 hash for every single clip the moment it's recorded. This hash is a cryptographic fingerprint. Change one pixel, and the hash changes. A claims handler or a police officer can verify that the footage you're submitting is exactly what your phone captured, unaltered.
When you export a dispute to send to your insurer or solicitor, Hawk bundles everything into a ZIP file with a manifest. Inside is your video clip, the integrity hash, the timestamp, and the GPS data. A technical expert can verify the lot. The GPS speed overlay isn't just a visual aid; it's part of the provenance chain that proves 'this is real, and it happened exactly when and how I'm telling you.'
We built this because we learned early that dashcam footage without proof of authenticity often gets questioned. Adding the overlay was step one. Adding the hash was step two. Together, they move you from 'I have a video' to 'I have evidence.'
Why continuous recording matters more than you'd think
A common mistake is thinking you only need footage of the moment something went wrong. But disputes rarely start at the exact moment of impact. They start a few seconds, sometimes a few minutes before. A driver drifting into your lane. Sudden braking. A vehicle rolling through a stop line.
Hawk records continuously while mounted. You don't have to press a button. This means when an incident happens, you have a rolling buffer of footage leading up to it, not just the collision itself. Your speed overlay is running for all of it. A claims handler can watch your speed trend in the seconds before impact, see that you were steady at 25 mph, then see the other vehicle enter your path. That context is what changes a contested claim into a settled one.
The continuous record also takes the thinking out of it. New drivers especially worry about missing the moment to hit record. They don't have to. Hawk is watching the road the entire time the phone is mounted and powered on.
Making it admissible, not just visible
Here's something that surprised us when we launched: many dashcam apps show speed and timestamp overlays as visual fluff. Pretty graphics that make the footage look professional but carry no legal weight. Hawk treats them as evidence.
Every speed figure you see on screen is logged to the manifest alongside the cryptographic hash. This isn't just so you can see 'I was doing 30 mph.' It's so a court can verify 'at time 14:37:23 on the 15th of November, the vehicle's GPS indicated a speed of 30 mph.' The precision, the timestamp synchronisation, the inability to alter it after the fact, these are what move a video from 'seems convincing' to 'legally admissible.'
We've also built integrations to make submission easier. On iOS, you can send your evidence directly to the NDSP police reporting scheme. No manual copying. No email fumbling. One tap, and your evidence file, complete with its manifest and hashes, goes where it needs to go.
When you're choosing a dashcam app, ask yourself what happens after the footage is recorded. Does the app give you the tools to prove it's real and what it says it is? Or does it just give you a video file and hope that's enough?