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Study: Traffic lights should respond to cars, not the other way around

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Re: Study: Traffic lights should respond to cars, not the other way around

#31

Post by WalterBright »

jacquesm wrote: post #26

In plenty of countries this is a reality already. Sensors are placed anywhere from a few meters to hundreds of meters ahead of the actual lights to determine the flow of traffic, there are 'green waves' which you can synchronize with to guarantee uninterrupted passage (both for congestion control and to save fuel) and there are adjustments made based on the expected flow from different routes depending on the time of…

The wire sensor buried in the pavement has been around since the 1960's, and nothing has improved since then.

You don't need to place sensors anymore, a simple camera can do it.

Re: Study: Traffic lights should respond to cars, not the other way around

#32

Post by jacquesm »

WalterBright wrote: post #31
jacquesm wrote: post #26

In plenty of countries this is a reality already. Sensors are placed anywhere from a few meters to hundreds of meters ahead of the actual lights to determine the flow of traffic, there are 'green waves' which you can synchronize with to guarantee uninterrupted passage (both for congestion control and to save fuel) and there are adjustments made based on the expected flow from different routes depending on the time of…

The wire sensor buried in the pavement has been around since the 1960's, and nothing has improved since then. You don't need to place sensors anymore, a simple camera can do it.

It's a bit more involved than that, nowadays there are many sensors instead of just one to detect a waiting car in front of the light, the speed gets measured as well as the number of vehicles.

As for a 'simple' camera, nothing that you deploy in all weather conditions is ever simple if it is to operate reliably.

Re: Study: Traffic lights should respond to cars, not the other way around

#33

Post by kes »

points wrote: post #15

Radical, but there's only one word needed here. ROUNDABOUT. Build some.

I live in a small midwestern town that has recently taken to the idea of roundabouts. At first, I was extremely pleased (having good experiences with them in Paris/French HW systems) but I quickly became discouraged when I realized that 90% of drivers had no idea what they were doing.

I now avoid certain routes through town because I'm afraid of getting in an accident.

Re: Study: Traffic lights should respond to cars, not the other way around

#34

Post by WalterBright »

WalterBright wrote: post #31
jacquesm wrote: post #26

In plenty of countries this is a reality already. Sensors are placed anywhere from a few meters to hundreds of meters ahead of the actual lights to determine the flow of traffic, there are 'green waves' which you can synchronize with to guarantee uninterrupted passage (both for congestion control and to save fuel) and there are adjustments made based on the expected flow from different routes depending on the time of…

The wire sensor buried in the pavement has been around since the 1960's, and nothing has improved since then. You don't need to place sensors anymore, a simple camera can do it.

Or even a directional microphone, or an infrared sensor, or a microwave radar, etc.

Re: Study: Traffic lights should respond to cars, not the other way around

#35

Post by tibbon »

As a motorcyclist, I'm going to disagree completely if the standard technology that is used to detect cars is used. Generally there's some sensor in the road that detects a large metal object above. If you're riding a 400 pound motorcycle, it doesn't trigger.

I've sat at lights for several cycles trying to get a left turn signal, only to be required to run the light (illegally) to get through while traffic built up behind me. Not cool. They need a better way of sensing cars.

Re: Study: Traffic lights should respond to cars, not the other way around

#36

Post by kijinbear »

pak wrote: post #29
marcinw wrote: post #9

Earlier quoted context omitted.

Why not just buy a neodymium magnet? This usually does the trick to trigger the sensor.

Then one day, you kneel down to check your engine oil, and bam, there go all your credit cards. There are downsides. I'd prefer if they just made the loops a little more sensitive. A 200 lb piece of metal would seem to suffice for a true positive...

Seriously, anything except a pedestrian should trigger the sensors. Car, motorcycle, bicycle, wheelchair, or a freight train from your subconscious trying to crush everything in its path... whatever it is, if it's sitting in front of an intersection and it's not on the sidewalk, chances are it's waiting for the green light!

Sure, you might get a false positive from time to time, but whatever causes the false positive probably shouldn't be in the car lane in the first place.

Re: Study: Traffic lights should respond to cars, not the other way around

#37

Post by njharman »

krschultz wrote: post #11

Not to sound like a radical libertarian but imagine a world in which roads were operated with some sense of incentives to actually MOVE TRAFFIC THROUGH. Lets have Tolls - but you get a refund when you are delayed. I imagine construction would suddenly be done 24/7 and be finished in half the time. Traffic light systems would be heavily automated/AI so that there isn't much traffic. Instead they give out construction…

Almost every place I've lived in the US construction does occur 24 hours, but maybe not 7. Commute and daily traffic require it. Maybe you're just not out 24/7 to see it?

Most traffic systems are automated and their goal is to MOVE TRAFFIC THROUGH. The minimal use sensors in the roads to help determine when to switch lights. The most advanced are integrated and use many metrics and algorithms in controlling traffic signals http://trafficinfo.lacity.org/html/atsac_1.html

Re: Study: Traffic lights should respond to cars, not the other way around

#38

Post by njharman »

kijinbear wrote: post #36
pak wrote: post #29

Earlier quoted context omitted.

Then one day, you kneel down to check your engine oil, and bam, there go all your credit cards. There are downsides. I'd prefer if they just made the loops a little more sensitive. A 200 lb piece of metal would seem to suffice for a true positive...

Seriously, anything except a pedestrian should trigger the sensors. Car, motorcycle, bicycle, wheelchair, or a freight train from your subconscious trying to crush everything in its path... whatever it is, if it's sitting in front of an intersection and it's not on the sidewalk, chances are it's waiting for the green light! Sure, you might get a false positive from time to time, but whatever causes the false positive…

With sensitivities that low false positives are triggered by cars in other lanes. Induction loops are very sensitive to variations. Believe me, I spent many hours on tweaking detectors.

Re: Study: Traffic lights should respond to cars, not the other way around

#39

Post by sliverstorm »

sigstoat wrote: post #14
sliverstorm wrote: post #6

If they remove timers from lights entirely, they better improve the sensors. There are already numerous lights that do not detect the presence of my motorcycle.

it seems as though in this case they're trying to detect 'platoons' or waves of traffic, so if you're traveling along in the vicinity of some cars, they can be detected, and you can still benefit.

Of course; that's how it is now. Car rolls up behind you and you're fine.

The problem is when you're alone and there are no other cars in your lane. If you're totally alone, you can run the red light, if there is other traffic just not in your lane you're screwed.

Re: Study: Traffic lights should respond to cars, not the other way around

#40

Post by sgibat »

sigstoat wrote: post #13
alecco wrote: post #4

Getting rid of cars as much as possible in congested areas is the best way. Promoting very good public transportation and prioritizing people walking and riding bicycles. If they optimize the flow of cars in a little time there will be more people using cars in those areas and no operations researcher can solve that bigger traffic jam. People, like any biological entity, adapt to the environment.

buses, trucks, emergency vehicles, bicycles on the roads, taxis, people going places too out of the way for public transportation to service and whatever other uses of the roads that aren't immediately obvious would all still benefit from this. smoother traffic flow and reduced time on the roads would also reduce accidents, which would require fewer vehicles be manufactured, which is a nontrivial environmental impact…

plus it will be easier to integrate the infrastructure when cars go automatic
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