I've seen quite a few intersections (Germany) that only feature one car road, but a crossing pedestrian/bike street that after pressing the beg button immediately begin to switch the light, resulting in a consistent, short wait (apart from signal priority stuff for busses). But anything more complicated, nothing comes to mind.

https://bicycledutch.wordpress.com/2016/06/21/traffic-lights... has plenty examples of things more complicated, for example:

“In the past, buses always got priority. Now every bus is tagged and the computer knows all the time-tables of every line. The system knows exactly when which bus needs to arrive at a certain intersection. The installation checks whether a bus is too early, on time, or running late and sets the lights accordingly.”

“On the cycleways we always have double loops, separated by 75 centimetres. That way we can measure speed and direction by combining the data the computer receives from the two loops. It also means we don’t need to reserve green time for a cyclist riding against traffic, away from the intersection.” And the pushbutton? “For cyclists that’s not really necessary. They’re only there for reassurance. You often see in the reports that people don’t even bother to push the button.”

But there the priority is pretty much everything else other than the beg button.

I can't help but wonder if such aggressive timings discussed in the article are good for people with disabilities. People often panic when rushed by a change to red.

I've experienced plenty of beg buttons that don't do anything other than activate the crossing light when that direction next goes green for cars. But also plenty where pressing the button takes immediate steps for the pedestrian: if the direction is already green for cars, the walk sign is turned on; otherwise, the current cycle ends and any intermediate cycles proceed with minimum duration; non-dominant directions will have longer minimum cycle time if the pedestrian button has been pressed.

In my experience, if the intersection processes car traffic dynamically, it will also process pedestrian traffic dynamically, and generally favor pedestrians. If the intersection has static timing, it's not going to do anything different for pedestrians. I recall driving in Milwaukee near UWM two decades ago, every morning I could count on the lights showing exactly the same thing at the same time. If I left my apartment at the same time, I'd get the same sequence of missed or made lights. Most other places I've driven had car sensors (usually loops in the pavement, but cameras are cheaper and less maintenance now), so there's no schedule to be learned, although the behavior is predictable if you learn the cycles and observe the stimuli. (Although, sometimes sensors are broken or miswired; there was an intersection near one of my employers where the cyclist button was connected as an left turn lane occupancy sensor; resulting in consistently wrong behavior. it's also not uncommon for a disabled vehicle to be located above a loop, or sometimes a construction / utility vehicle to be parked above a loop; some control systems can adapt and filter that out, but many don't.)

I don’t see beg buttons in Sydney that turn green mid-phase — where are these? You always have to wait for a complete phase (which can be shortened, with no traffic and no area phasing) before the pedestrian signal is allowed to turn green again.

The only partial exception is pedestrian-only crossings and then only if you are in the part of the phase where enough time still is available to return cars to green.

I also wrote a blog post on beg buttons in the Sydney CBD: https://jakecoppinger.com/2022/12/sydney-cbd-is-bringing-bac...

(194 comments on HN: https://news.ycombinator.com/item?id=34058004)