>> Using cars at all isn’t the best we can possibly do.
> Granted. But any solutions to that are several orders of magnitude more expensive.

Strong disagree. Right now - the state of Covid work-from-home - is partial evidence. Other countries and some US cities like New York offer more evidence. Try to estimate the amount of private money spent on cars and car maintenance annually by all citizens, and guesstimate what we could buy in shared transportation resources, with the same amount of money. It would be extraordinarily difficult to change America's habits, but I don't buy that it would be more expensive. I'd argue the opposite, we are currently spending way more money than necessary in return for fictional ideas of personal freedom.

> I'd say ranges of 70 - 100 mph

Well, we're already there in much of the west, we already match speed limits on the Autobahn. In urban cities, I can't think of a highway I've ever commuted on in the east coast or west where it's possible to safely sustain > 70mph for long stretches, and I've never, in decades, had the opportunity to do that while commuting. Raising the speed limit simply wouldn't change that.

The radius of turns, and weather conditions are confounding factors for your wish. You're advocating speeds that don't leave adequate reaction times for unforseen situations, crap in the road, motorcycles, large trucks, or any number of things that regularly occur in the real world.

> Given the above, you'd arrive in 70% of the time at 100 mph, no?

Extremely unlikely, you're jumping to an invalid conclusion that raising the speed limit on the highway by a percentage would yield a proportional average travel reduction. To achieve that average, you typically have to peak much higher. You're not accounting for the off-freeway portion of your trip. And you'd have to perfectly sustain top speed the whole time, which is most places and in most traffic not possible, unless you're making assumptions you haven't explained yet.

I'm still not seeing the money. You've made a hand-wavy purely theoretical argument with logical gaps that somehow more money would appear in my pocket if only I could drive faster. How would that happen? What makes you think that people wouldn't respond by moving 30% further away for even cheaper housing (which would then rise in price due to increased demand)?

> I look at traffic as a failure of transportation policy.

Why? There are more cars on the road every year, that will automatically yield more traffic. And it's just as much a failure of transportation infrastructure, which was intentionally crippled by the lobbying of automakers in the US. It's also a failure of urban planning. We wouldn't have to commute if we lived closer. How would increasing speed limits as a policy fix traffic?

> Because they're substantially funded by speeding fines?

I believe that claim is false in most states. Can you provide a source please? The Highway Patrol in most states is primarily funded by taxes, and tickets in metropolitan areas are normally a small minority of their general fund. Often the revenue from fines goes to other city & state projects, and not back to the Highway Patrol.

Your theory fails to adequately explain why the Highway patrol is constantly begging people to slow down and be safe, posting signs about limits, being as obvious as possible about their speed monitoring, and not enforcing anywhere near as much as they could. You may want to take a few minutes to read the annual Highway Patrol report for your state and a few others. They are dominated by a focus on safety.

You're already trying to sell me a bridge with a gap in it. Call me completely unconvinced, let's agree to disagree.