I’ve seen the number of induction coils increase drastically over the years in The Netherlands. They are quite easily recognizable, as there’s typically a solar panel on a pole, that appears to provide power to the system.
Considering there’s a wide variety of vehicles on the road, surely each variant must have (slightly) different characteristics when passing over the coil; especially when in a specific place at a specific time.
And given that they are situated at highway exits (see picture) or after entrances, and road users unable to exit and enter elsewhere, it would be trivial to track the bulk of a vehicle’s trip.
This in context of ALPRs (in different forms) being in place at strategical locations (large junctions or at bridges or tunnels, and parking), and the address of vehicle’s owner; you’d be able to connect the dots, and end up with a pretty complete picture.
It’s not the cameras that are tracking you, it’s the machine vision that reads licence plates, and that has not been around longer than you’ve been alive.
All these loops can detect is if a massive chunk of metal moves over them, no PII. Knowing how many cars use a road is critical in knowing if a road is congested or not, and that helps make roads better for everyone. It’s not part of the surveillance machine. This kind of sensor is no more nefarious than the 100 year old sensor in your toilet that stops filling the tank when it is full.
Take your tinfoil hat off.