Earlier quoted context omitted.
Why does the slippery slope concept surprise you? It actually happens often - banning smoking indoors, for example - started in just one city, once they tweaked the model and overcame the legal challenges, it spread rather quickly. Legalized casinos, same thing. Uber, drinking age, pot legalization, more. Why would toll roads or congestion pricing be different? (Idaho's Sun Valley probably already implements somethin…
These would be examples of normalization, not a slippery slope. The OP's example makes this clear (from "congestion pricing in NYC" to "they're going to take my car," not "congestion pricing in NYC" to "congestion pricing elsewhere"). (Regardless, I think the answer is simple: congestion pricing is only economically viable when an area is simultaneously congested and has alternative transportation methods that would…
Sounds like an arbitrary distinction, but in any event, it was the OP who used "slippery slope" to refer to going from "congestion pricing in NYC" to "they're going to take my car."