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.
As someone who works in industrial automation, you’re completely going overboard with this.
I can almost guarantee that this goes to a pulse counter. Car drives over, induction coil gets activated and a pulse is output to a counter.
The sheer cost of putting in a PLC to get the high sample rate required to analyse a car is enough to make it extremely unlikely. Not to mention the requirements and costs of the sensor go way way up.
It’s just an automated counter, nothing more.
Adding to that: While each individual car would have a slightly different inductance value, the car’s body is not the only factor.
You’d need to also account for car speed, air humidity, environment temperature, whether the car passes perfectly on the coil or slightly off to the left or right.
Too many variables to account for