The law comes first
In Great Britain it is illegal to hold and use a phone, sat nav or similar device while driving or riding, and the prohibition is broad: it covers holding the device for almost any purpose, including when stopped at lights or queuing in traffic. GOV.UK sets the penalty at six penalty points and a £200 fine, rising to a court appearance and a larger fine in some circumstances. A driver within two years of passing the test normally loses the licence outright at six points.
A device used hands-free — in a cradle or a dashboard holder, operated by voice — is permitted, but that permission is conditional. The driver must remain in proper control of the vehicle, and the police can act if they judge that control was lost, regardless of how the device was mounted. “It was in a holder” is not a defence to not being in control.
Before setting off
- Choose the route and alert preferences while parked, with the handbrake on and the engine off.
- Mount the phone so it does not obstruct the view of the road or the instruments, or use audio only.
- Set a volume you can hear over road and climate noise without needing to adjust it later.
- Connect power and download any map data you will need, so the app does not prompt you mid-journey.
- Silence notifications from everything that is not the journey. Most phones have a driving mode for exactly this.
- If a passenger is present, agree that they make any changes en route.
While moving
Keep your eyes on the road and treat any alert as supplementary information. Posted signs, temporary limits, roadworks, weather and instructions from police take priority over anything a screen says. If the app needs attention, it can wait until you have stopped somewhere safe — and a lay-by reached two minutes later costs nothing.
Audio alerts are preferable to visual ones for the simple reason that they do not compete for your eyes. A well-configured setup should let you complete an entire journey without looking at the phone once.
The failure mode to avoid
An alert is meant to remove a surprise, not to create a task. The moment it prompts a glance down, a decision about whether to confirm something, or a sharp reaction, it has produced exactly the risk it was supposed to reduce.
The same logic applies to the alert itself. Braking hard because a warning arrived late is more dangerous than the speed it warned about, particularly with traffic behind you. If alerts are consistently arriving too late to act on calmly, the setup is wrong: increase the warning distance, or turn off the categories you do not act on, rather than driving in a state of readiness to brake.
Why alerts do not change the limit
An alert is informational. The signed limit and the applicable law remain controlling whether or not any alert appears, and an absent alert never means an absent limit — mobile enforcement moves, datasets lag, and coverage varies. Driving to the alerts rather than to the signs inverts the tool: it makes the app the authority and the road an afterthought.
The useful mental model is a passenger who occasionally says “there's a limit change coming up”. Helpful, worth having, and not someone you would hand the steering wheel to.