Hacker News Reader

Comment by Svip | Hacker News Reader

Americans should consider shorter junction cycles instead. My experience in the US is that traffic light cycles are long, leading to impatience, and long queues building up at lights when they turn red, which may even spill into a junction further down, leading to further congestion.

That's in comparison to Europe, where the traffic light cycles are short, meaning less cars get through on each cycle of green, but at least everyone feels they don't have to wait quite as much. Red-light cameras are also rare in Europe, I have only encountered them in Germany, but they could be elsewhere.

View on HN

This would feel better but isn't it less efficient because then there's more stopping and starting? Like instead of waiting at an average of 5 lights for 60 seconds, you wait at 10 lights for 30 seconds, which means you spend twice as much time decelerating/accelerating to/from a stop.

But it will feel like more is happening, thus lowering impatience, and it will also mean that even if the lights are synced, it's harder to get up to a dangerous speed in built up areas. So it's also safer.

In cities, I don't really care about making it convenient for drivers, but lowering their impatience will make it safer for everyone.

Oh yeah, in the city you might have a point. I was picturing a limited-access road in a suburb, with lights spaced pretty far apart.

https://en.wikipedia.org/wiki/Limited-access_road

Seconded (as a European). I also found the cycles in the US very long, they are optimized for batch throughput, but do not take human nature into account. I noticed people are much more likely to keep driving when the light turns yellow and then red, than in Europe — probably because they expect a long wait if they miss the light. This is especially dangerous to pedestrians and bikers.

Removing the traffic cameras seems like a bizarre move: if anything, I'd place more of them, with more severe penalties.

Spending time on both continents - I prefer the American approach in this. Starting and stopping slows down the throughput, also, as a driver, I prefer to sit still for 2 minutes than to stop and go every 20seconds.

Side-story, on the Burning Man entrance, there is always a multi-hour traffic jam (one road, thousamds of cars, for 70km or sth). A few years ago they introduced a system where they only allow the cars to move once an hour. That way, you drive for a few minutes, and then stop and chill until the next movement window. Way better than having to be constantly alert for next 100m moveme t every few minutes.

I dont know how this helps. We do probably need an adaptive cycle, so that it can adjust based on traffic. On major roads, it can keep ot green for longer.

In south bay, el camino comes to mind, and it can be much better.

A lot of junctions in the US have 'intelligent lights' (I don't know the exact term), where there are plates on some lanes, so it only turns on for a lane if there are cars in it. That is mostly noticeable for left-turning lanes.

But in Europe, most traffic lights are programmed to act differently based on the time of day, hence allowing a smoother traffic in rush hour. Or in some European cities, the lights will switch to flashing yellow at night.

I don't think traffic lights need to be that smart, just scheduled. I have definitely not heard that European traffic should be significantly worse than US traffic.

The problem is that American land use is organized in a way that basically requires driving. If you want to do something as trivial as travel from one supermarket to another across the street, the roads are high-speed, the crosswalks are far away and inconvenient (fast walk cycle time, slow red time), and on top of that you have to cross large parking lots to get to and from the front door. Just look at the environment between this Trader Joe's and Whole Foods: https://www.google.com/maps/@40.86918,-73.1275739,464m/data=...

We make everyone drive for the shortest of trips and then are shocked that we have so much traffic.

When I lived in Phoenix, they had those. The leading left green arrow would be triggered when there were three cars or more waiting to turn left, otherwise you would get normal green that needs to yield to oncoming traffic and it usually took the entire light cycle for traffic to clear.

The first car would stop at the normal line. The second car would wait a full car length behind and only move forward when a third car arrived. This way, you could trigger the "intelligent" light with only two cars instead of three and save yourself a full light cycle.

>I don't think traffic lights need to be that smart, just scheduled. I have definitely not heard that European traffic should be significantly worse than US traffic.

They absolutely are scheduled in the US anywhere that's population dense enough. Compensating for rush hour traffic flow is a huge thing that requires the adjustments.

The US uses all of those methods in conjunction.

And in my opinion, the problem is that the cycle itself is too long. If they merely tweaked that, the impatience would be lowered, and you might even get smoother traffic.

The cycle is entirely up to the local Department of Transportation be it a city, town or state. Where I live we have short cycle lights at heavy intersections and long cycle lights at intersections where keeping the primary/heavy road going longer is 100000% more worth it than some side secondary road with 3 cars every hour. There are also plenty of complex areas where all the lights on a road are interconnected for miles and the timing is set to match between them to more efficiently feed cars onto highways and move them along.

In Houston we have also lights programmed to rush hour so that in the core downtown area, lights are timed so you can make it from one end to the other without hitting a red light if you drive the speed limit.

The problem is that I don't think these lights can be remotely programmed, so after bad weather (tropical storms, etc) the power will inevitably go out and the lights will reset. And then it feels like they only get fixed when someone feels like making a 311 call. Repeat ad nauseum.

The one problem with us that might be different from europe is density. People usually work in further locations compared to europe, and lack of public transport is a major bummer.

I think schedule-dependent is probably what i mean. Lanes here do have 8 shaped measurement systems to detect near real time traffic, and in theory government could collaborate with google who has this data as well. Run some simulations, and extract schedules and that should be a big improvement(assuming it is not already done)

I‘ve experienced some of the most insane red-light cycles in fly-over-usa.

The one I still remember to this day, was one that took 15 minutes. It was 2am at an left-turn into a t-intersection. There was of course no traffic at all. We haven’t seen a car for 30 min. before and after, but the fear of some traffic cop just waiting for us to crack was bigger than our impulse to end this nonsense.

Till this day it haunts me that there might have been a traffic cop sitting in front of us all the time, because this insane red-light was the perfect trap. What else he‘d be doing all night anyways? It took so long, we went from frustration to laughing multiple times. And then we’ve started counting the clock.

Roundabouts would help too. There's a lot of random traffic light controlled junctions in lower traffic spots all over the place that could easily be replaced by a roundabout without any lights.

Even where lights are involved, roundabouts drastically change the types of accidents experienced to the less-deadly rear-ends instead of t-bones (while also reducing the overall number of accidents too)

There are some in the UK but they're not that common. I usually see them on high-volume arteries in and out of London.

that's incorrect in urban areas. Most modern areas use cameras and sensors and traffic information to decide lights switching to adjust for traffic. Most rural areas dont' have the money for such data/sensor setups and just set up "common sense" timers

Reply on news.ycombinator.com