A method for primarily sensor-based navigation of a vehicle on a road surface, the method comprising: • in a first time period, collecting geophysical position data using a GPS receiver of a navigation device; • in the first time period, collecting a first set of accelerometer data using an accelerometer of the navigation device; • analyzing the first set of accelerometer data to produce a first set of vertical vehicular motion data; wherein vertical vehicular motion data describes motion of the vehicle perpendicular the road surface; • generating a mapping association between the first set of vertical vehicular motion data and the geophysical position data; • in a second time period after the first time period, collecting a second set of accelerometer data using the accelerometer; • analyzing the second set of accelerometer data to produce a second set of vertical vehicular motion data; • calculating an estimated location of the vehicle by analyzing the second set of vertical vehicular motion data in light of the mapping association • generating a set of previously traveled routes, each previously traveled route of the set of previously traveled routes associated with geophysical positions previously mapped to vertical vehicular motion data; • receiving, at the navigation device, a travel source and a travel destination; • determining that a first previously traveled route from the set of previously traveled routes intersects the travel source, the travel destination, and the estimated location of the vehicle; • in response to identifying the first previously traveled route, switching off the GPS receiver; and • navigating the vehicle according to the first previously traveled route, wherein navigating the vehicle according to the first previously traveled route comprises navigating based on vertical vehicular motion data without collecting additional GPS data. • in a first time period, collecting geophysical position data using a GPS receiver of a navigation device; • in the first time period, collecting a first set of accelerometer data using an accelerometer of the navigation device; • analyzing the first set of accelerometer data to produce a first set of vertical vehicular motion data; wherein vertical vehicular motion data describes motion of the vehicle perpendicular the road surface; • generating a mapping association between the first set of vertical vehicular motion data and the geophysical position data; • in a second time period after the first time period, collecting a second set of accelerometer data using the accelerometer; • analyzing the second set of accelerometer data to produce a second set of vertical vehicular motion data; • calculating an estimated location of the vehicle by analyzing the second set of vertical vehicular motion data in light of the mapping association • generating a set of previously traveled routes, each previously traveled route of the set of previously traveled routes associated with geophysical positions previously mapped to vertical vehicular motion data; • receiving, at the navigation device, a travel source and a travel destination; • determining that a first previously traveled route from the set of previously traveled routes intersects the travel source, the travel destination, and the estimated location of the vehicle; • in response to identifying the first previously traveled route, switching off the GPS receiver; and • navigating the vehicle according to the first previously traveled route, wherein navigating the vehicle according to the first previously traveled route comprises navigating based on vertical vehicular motion data without collecting additional GPS data. <EOS>