Partially... - Satnav, is based on GPS which has a degree of error, it might place on a 4 lane road or a 2 lane road immediately parallel to it, with a drastic

Partially... - Satnav, is based on GPS which has a degree of error, it might place on a 4 lane road or a 2 lane road immediately parallel to it, with a drastically different speed limit. - Satnav has no way of adapting to temporary lane closures or roadwork speed limits. That's the reasoning for combining GPS with TSR camera data, in these 'intelligent speed' ADAS systems.