IMO, the problem is "how do we allocate road so that high utility use gets precedent over low value use, without defining high/low value as 'rich/poor person wants to get from a to b'"
Expiring credits is an idea, as are a lot of options. Designed markets are a devil-in-the-detail endevours. A market is a good tool for this job, that's why economists and wonks like tolls. But, not every market needs to be the market. In this case, The Market is probably worse than the no market free-for-all.
I mentioned the option of transferability for completeness. I'm not advocating for or against it. I am noting that it would change the dynamics somewhat.
Your #2 is a rather more involved and tangential discussion. Historically, it has a strong tendency to end in tears, or worse.
I actually think this was a bit of an aha moment for me re: cryptocurrency and government.
It's possible for a government to setup a market for a public good, create a currency for that good and distribute that currency equally to people. All without spending actual currency(ignoring administrative costs of setting up a blockchain).
The value of the public good for people then determines the USD exchange rate, but poor people are never excluded from using the good and at the same time you are not massively inflating the money supply.
edit. In fairness, nothing about this requires a cryptocurrency/blockchain. It's more a general argument in favor of governments charging for public goods by creating custom (maybe fiat) currencies which they distribute equally to all citizens.
There might be administrative and/or psychological benefits to running all these custom currencies on blockchains.
Creating a whole new kind of currency with its own special rules is a huge undertaking. Not to mention the ongoing pain-in-the ass cost to every citizen when they have to carry around and think about a new special kind of money that can only be used for one thing.
If you did that with roads, what's stopping the upper income distribution from excluding everyone else from entire cities? A gated community concept might scale to an entire upperclass city with a private airport, hostpital, and 1000$ entry fee to keep out the poor. This might even effectively reduce overall costs for the municipality since homeless and property crime would be greatly reduced.
On the other hand if other currency is used, it makes everyone easily trackable.
I think the dumb pipes model still has some advantages.
zkSNARKs for the rescue! It's surprisingly easy to roll with that. (See Zcash, Monero, ETH and whatever.)
https://en.wikipedia.org/wiki/Ramp_meter
I'd focus more on one of my other punts above: ways of drawing a correspondence between traffic and congestion, on the one hand, and alternative transit options (buses, rail, cycling, telecommuting, etc.) on the other. Market pricing signals fail to provide the coordination many of these options require. Typically, planning-based approaches are required.
I like driving, but I'm very bad at managing the stress associated with owning a car, finding a parking spot, sitting in congestion, trying to be there in time (speeding to gain a few minutes that makes no sense), hence I don't have a car.
And I wouldn't live in a place that requires one.
And I can't understand how the US is so deep in the hole with regards to mass transit / public transport, commute time, etc.
Sure, I know, it's a classic coordination problem, and I'm probably very biased by having access to a very cheap and efficient public transit network.
2) What is wrong with wealth accumulation? If credit recipients would rather do that than drive on roads they should be able to do so. They's how they get less poor!
3) If they credits are transferable then you are effectively giving people money. Just in an ass-backwards and overly confusing way.