This Bad Idea has been floating around for a few years. Some idiots built a product and have been aggressively lobbying governments to take them up on it, and even though governments really like being able to do big brother tracking of everywhere everybody drives, they still haven't bought it. They've tried selling them to Oregon and California, they've tried selling them to San Francisco for congestion pricing for drivers in the crowded downtown business district, they've tried selling them for highway toll collection, they've tried selling them to the Feds. They've tried selling it to states as revenue enhancement ("People buy Priuses which use less gas, so you're collecting less gas tax, so buy our thing instead of just raising the tax rate!") There's always at least one legislator or bureaucrat who likes the idea and tries to convince their fellow legislators or bureaucrats, which is enough for the pushers to put out a press release.
But because these guys really want to sell their product, the good guys have to keep squashing it. It's usually not hard, because it's a terribly unworkable idea, but the Big Brotherness of it is really obnoxious, and as far as I can tell, wasn't even the purpose of this system.