Most drivers now use navigation software that reports speed cameras, road works, police presence and hazards, largely gathered from other users. The features are widely available free, and the legal position is more varied than people assume.
What the free apps provide
Major navigation applications report fixed speed cameras and average speed zones, community reports of mobile enforcement, crashes and obstructions, live traffic, and the current speed limit against your speed.
Accuracy for fixed installations is generally good, since they do not move. Accuracy for mobile enforcement depends entirely on how many users are on the road at that moment, so it is strong in cities and weak in rural areas.
The legal position varies
This is the part worth checking. In most of the United States, apps reporting camera and enforcement locations are legal, though separate rules restrict radar detectors in commercial vehicles and in a small number of jurisdictions.
Several European countries restrict or prohibit devices that specifically warn of enforcement locations. In some, apps must display zones rather than precise camera positions. In others the feature must be disabled entirely.
If you drive across borders, check the rules for each country rather than assuming your home settings are acceptable. Penalties in some jurisdictions are significant.
Mounting and distraction rules
Separately from what the app reports, most jurisdictions regulate where a device may be mounted and prohibit handling it while driving. Windscreen mounting is restricted in several places because of obstruction rules.
Set your route before moving and use audio prompts rather than looking at the screen.
Free versus paid
The major free applications cover camera and hazard alerts adequately for most drivers. Paid options tend to add offline maps, more detailed enforcement databases, or specialised routing for larger vehicles.
For ordinary driving, the free versions are sufficient. Before subscribing to anything, check whether the feature you want is already in a free app.
Data and battery considerations
Community-sourced alerts require a data connection and consume battery. Offline maps solve the first problem but disable live reporting. A car charger solves the second.
Be aware that these applications collect location data continuously. Review the privacy settings, particularly around sharing driving data with insurers or advertisers, which some services offer as an opt-in.
The obvious point
These tools are most useful for what they tell you about the road: an unexpected queue, a crash ahead, a changed limit you did not notice. Used that way they genuinely improve safety.
Used purely to avoid enforcement while speeding, they solve the wrong problem, and they do not report every camera.