sure, but all this relies on a fundamental assumption: that the entity running the toll booth already has the means to collect outside the point of transaction

sure, but all this relies on a fundamental assumption: that the entity running the toll booth already has the means to collect outside the point of transaction pretty reliably. so, it's either a highly connected society, or more cynically, a high surveillance society. in a sense it's a self fueling machine: you need to have that data linked to collect outside the tool booth, which requires data linked from DMV or whatever local equivalent is, then strong (enough) justice system/penalties/enforcement to get those who didn't pay at toll booth to pay, etc. you can bet that the smarter investment, despite these drawbacks, in less "advanced" countries is to have manned tolls because there's a high probability that they won't be able to collect using the sort of infrastructure upon which this relies.