Old GPS units were good at the time, but smartphone navigation is leaps and bounds ahead of what we used to have in terms of features.

The solution to this dilemma isn’t to forswear GPS and all other technology for the rest of our lives. We can’t keep people from using smartphones and GPS navigators, nor should we really want to.

An accelerometer measures the acceleration of your phone. It does that on three axes: horizontal, vertical, and forward/backward. It also senses vibration, tilt, and free fall. Being able to calculate ...