Different biases

Travelling by car between London and home in France requires navigating through the jumbled ring roads surrounding Paris. As I like gadgets, I have a couple of GPS route planners (one in the car and one on my phone) and to date, not once have the devices agreed on the same route. To be fair, both are intelligent devices, aware of roadworks, traffic jams, accidents, etc – but it is still curious they cannot advise on the same route using the same data, due to different biases in the software.