I highly recommend Traffic Light Doctor on YT, if you're into this sort of thing.
And the roads themselves are good in NL (huge contrast when I moved to Montreal, where we'd have a metal mesh underneath bridges to catch falling concrete)
In the US, we have many more lights due to the road layout (grid). There are more than 3200 signaled intersections in my county in California alone despite being 1/14th of the land area of the NL.
The robot also estimates that there are 300,000 signaled intersections in the US. We honestly don't know how many there are because they are all operated by different agencies.
For US arterial roads iVRI has limited benefit. So the focus in the US has been on V2X development which focuses more on crash avoidance and has much higher installation costs due to latency requirements. In the end there's a lot of low hanging fruit here in the US if signals could just be retimed.
https://transportationops.org/publications/2012-national-tra...
NL has one procurement entity. In the US there is no single coordinating entity to standardize traffic lights. Each state standardizes its own lights and then each municipality handles its own procurement.
Lowering the number of traffic lights in and of itself is a good idea. Overpasses and (turbo)roundabouts, clever right of way, better road hierarchy; there are lots of alternatives that may provide better throughput and more safety for a given intersection.
The Netherlands as a country with 18M inhabitants is best compared to a big city with the surrounding metro area.
There's an annoying one near me at the bottom of a hill where anyone approaching from the sidestreet will ruin the descent on bicycle, even if they were turning right (from a dedicated turn lane) and didn't need the light to change for them at all. Another is a former police station now used as a park facility. Cars entering the parking lot only need to barely brush over the sensor and the light changes instantly for no reason because they never reprogrammed the light when the police left.
Have you really never seen what happens when something grows organically without global maintenance? Not saying that this is what happened in Germany, but "it takes work" sounds naive.
It doesn't take work to write a crappy codebase: all you have to do is add code without really caring about the overall architecture.
Or said differently, if you can fix the German traffic engineering, you should apply there because I'm sure they would be happy to have an easy and perfect solution.
From what I've seen about US traffic, there doesn't seem to be much to be envy of.
Most intersections are atrociously designed. Protected left turns everywhere, with their own lane and their own traffic light causing slowdowns and triggering also when nobody needs them.
Many pedestrian crossings could be moved 10m further from an intersection, allowing up to a couple of cars (wishing to turn right) to wait on the pedestrians without blocking all the people who were just going to proceed straight ahead. On the other hand, this problem would often not even occur if we hadn't wasted a lane for a protected left - there now would be a dedicated lane for those going right.
Right-on-red is legally permitted (there's a dedicated street sign for it) but almost never implemented. It's so frustrating.
An overwhelming majority of the traffic lights I encounter is completely non-adaptive. I wait an average of 40 seconds every morning at a specific one which is, in aggregate, causing entire human lifetimes of wasted time on a monthly if not weekly basis.
Zebra crossings are often outfitted with a pedestrian traffic light which is red (rather than off) by default. If the road is completely clear, you could just cross, but no, you must press, wait up to half a minute, and finally it turns to green for you. Now you also stopped a car or 2 which need to wait for your green to finish. If it defaulted to OFF, you could have crossed 20 seconds ago without interrupting anybody's life, and the traffic light would still still be available for elderly or disabled (or whomever wishes to press and wait, while not having it as a default).
...I could continue.