What you're decribing plainly doesn't happen. That's part of why people buy fancier cars in the first place - to be treated better by those who judge them on it.
But that's also the part I don't really care about. I was objecting specifically to the original point that rich people shouldn't be able to buy better treatment.
Anyone can use toll roads - it doesn't matter what car you drive, where you came from, or where you're going, the price is the same for everyone. Price per mile, flat rate, whatever - if it's non-discriminatory, it's neutral!
Non-neutrality is when a toll road charges more because of the car you drive, where you came from, what you're carrying, or where you're headed - or letting certain people jump the queue based on those criteria.
It's not OK to give a discount to BMW drivers because they drive a BMW. If BMW drivers are the only ones that can afford the price - that's OK. But if a Corolla driver comes along and pays the price, they better get exactly the same service.
(The analogy does break down at vehicle weight - cars can be long/short and heavy/light, packets are only long/short)