Yes, Traffic Lights Simulator is designed to work on a single device too. However when you use two devices, they can synchronize the traffic lights state between them in real-time.
Does this app use the internet?
No, Traffic Lights Simulator works completely offline. All synchronization happens locally on your device without any internet connection required. Your data stays private and never leaves your device.
Is my data stored anywhere?
All data is stored locally on your decive. Nothing is transmitted to external servers, and your information remains completely private on your device.