Average speed camera calculator
Average-speed cameras (also called section control, SPECS, Tutor or radar de tramo) don't measure your speed at one point — they measure your average across the whole stretch between two points. To stay under the limit you have to keep the average down, not just slow for the camera. Use the calculator below to see the average you're on and the steady speed to hold.
Work out your average
Enter the corridor length and its limit. Add how far you've come and how long it's taken to get the speed to hold for the rest.
Everything runs on your device. Nothing is sent anywhere.
How average speed cameras work
A pair of cameras reads your number plate as you enter and again as you leave. Divide the distance between them by the time it took you, and that's your average speed. If that average is above the limit, you can get a fine — even if you were under the limit at every single camera.
Entry is time-stamped
The first camera records the moment you enter the corridor. No fine is decided here — it's just the start of the clock.
Exit is time-stamped
The second camera records the moment you leave. The system now knows your exact time over a known distance.
The average is the verdict
Distance ÷ time = your average. Over the limit means a possible fine; braking hard for the last camera changes nothing.
How to stay under the limit
The trick everyone gets wrong is slowing down only at the end. Because the camera measures the whole corridor, a fast first half can already put your average over the limit before you ever see the exit camera. Two habits keep you legal:
Hold one steady speed. Pick a speed a little under the limit and keep it for the entire stretch. A steady 95 in a 100 zone is calm, legal and predictable.
Watch the average, not the speedo. If you did go faster early on, your speedometer can read under the limit while your average is still over it. The only number that matters at the exit camera is the average — which is exactly what Safe Average shows you live as you drive.
Where you'll meet them
Common questions
How is my average speed calculated over a corridor?
Divide the length of the corridor by the time you took to drive it. For example, a 12 km corridor covered in 8 minutes (0.133 h) is an average of about 90 km/h. Average-speed cameras do exactly this between the entry and exit points.
Does slowing down before the last camera help?
No. The camera measures your average over the entire corridor, not your speed at the exit. If you drove fast early on, braking at the end can't undo the time you already saved — your average stays high. Holding one steady speed for the whole stretch is the only thing that keeps the average down.
What speed should I hold to stay under the limit?
A little under the posted limit for the whole corridor. If you've already covered part of it quickly, the safe speed for the rest is lower — the calculator above works it out from the distance and time you've done so far.
Can my speedometer read legal while my average is over the limit?
Yes. Your speedometer shows your speed right now; the camera cares about your average since the entry point. That's why a live average — like the dial in Safe Average — is more useful inside a corridor than the speedometer alone.
Is Safe Average a speed-camera detector?
No. Safe Average is a compliance and safety assistant that shows your own rolling average so you can hold a legal speed. It does not detect live cameras, and any camera awareness is limited to routes you save and only where local law allows.
See your average live, the whole way.
The calculator shows the maths. In the car, Safe Average shows your average on a single dial as you drive — green while you're under, and the exact steady speed to hold. On the App Store now.
One-time $4.99 · no subscription · no ads · your route is never stored.