You’re forgetting a step - which, being a hardware designer instead of a lawyer, is understandable.
The fourth amendment means that there should never be a situation where you are arbitrarily required to provide the government access to, or information about, the ways that you use or modify private property like a vehicle.
No I did not forget it, I was responding to an technical argument with an technical answer. And I am the type of person who wouldn't design such a system if you held a gun up to my head.
Of course there is a legal layer to this as well. But given how the US legal system treats other constitutional rights that ought to be valid for everybody on American soil at the moment, I thought I'd skip that for now, because apparently something being a constitutional right doesn't make it so.
We already require breathalyzer interlocks be installed for habitual DUI drivers in a majority of states. This is an extension of that same legal principle. Road access is a privilege (as evidenced by the requirement to have a driver’s license and vehicle tags).
The fourth amendment means that there should never be a situation where you are arbitrarily required to provide the government access to, or information about, the ways that you use or modify private property like a vehicle.