Aggregating the speed data is usefull too. e. g. based on lots of location and speed data, you can tell that traffic on Highway 1 is moving, but on Route B it isn't; and route incoming cars accordingly.

Or gather data on average speeds and numbers of journeys by time of day for capacity planning.

It can be used for evil; but there are legitimate uses too. it's a hard problem to get the data out to only where it can do good.