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# How many of you feel the need to "re-engineer" the stop lights at intersections?

• Posts: 12,677
I just returned from Vietnam where our guide told us the following rule applies to traffic lights:

Green - "I can go"
Yellow - "I can go"
Red - "I can still go"

They seemed to obey that rule pretty much except for a few big intersections.
• Posts: 14,081
When we were there ~7 years ago, I don't recall traffic lights. Traffic went everywhere.

They had local guides near major roads and centres to help visitors cross the roads. You just walk across steadily, and they drive around you. Quite scary really
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• Posts: 22,044
Here's a scenario I'd like to see resolved:

You're approaching an intersection. Just before you get there, the green light turns yellow. By law you're not supposed to enter the intersection, but I do. A cop sitting across the street sees the infraction, pulls me over, and issues a citation. I decide to contest the ticket by going to district court. When there, I request the court's indulgence to question the cop. Here's how I think the questioning might proceed:

Me: "Officer X, where was I relative to the intersection when the light turned yellow?"

X: "You were about five feet from the stop line."

Me: "How fast would you say I was going?"

X: "Well, I didn't have my radar on you, but I would guess about 25 miles per hour."

Me: "I see. When I took driver's training I learned that it takes one car length for every 10 miles per hour of travel to stop safely. Would you agree that this is a reasonable estimate?"

X: "Yes, I learned the same thing."

Me: "So if I were going 25 miles per hour, how many car lengths would it take for me to stop safely?"

X: "I guess about two and a half."

Me: "Now, the average car is about 15 feet long. Would you agree to that figure?"

X: "I suppose that seems reasonable."

Me: "So if I can multiply two and a half by 15, which works out to 37 and a half feet, would that give me a reasonable distance that it would take to stop safely?"

X: "I suppose it would."

Me: "But you said I was five feet from the stop line when the light changed, correct?"

X: "Yes."

Me: "So subtracting five feet from 37 and a half feet, would put me about 32 and a half feet into the intersection before I could come to a complete and safe stop, correct?"

X: "Hmm. I suppose it would."

Me: "Does coming to a stop in the middle of an intersection when the light is changing seem like a good idea to you, Officer X?"

X: "Well, no, of course not."

Me: "Your honor, I would submit that the law, as written, is either flawed or requires a different interpretation about where the actual intersection boundaries are. I would claim that the real, legal boundaries lie back from the stop line by a distance equal to 15 feet for every ten miles per hour of the speed limit at that intersection. Moreover, based upon that claim, I would further claim that anyone within those boundaries of the intersection should be deemed to be in intersection itself and free to clear the intersection by driving through it when the light changes, instead of having to slam on the brakes in a possibly unsafe manner. Based upon these assertions, I request that the citation issued to me be dismissed. Thank you, you honor."

I rest my case.
-Phil

Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
• Posts: 2,081
what the hell have facts to do with legislation?

anyone?

Mike
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• Posts: 1,953
A stop light almost killed me. So, I'm not in favor of them.

I was three blocks from home. For years the turn left signal and the green light were synchronized. And then, without asking me, some a* changed the sequence. I was sitting there, minding my own business, noticed traffic to my right moving so I went ahead.

BAM... the front of my vintage van was taken clean off. I was fine, but left with an abiding hatred of traffic engineers.

We need to get rid of turn signals as well. I got stopped in the middle of nowhere for not "signaling a turn." There was nobody with three miles to f'''ing signal. Nobody ever signals me... Constantly all day long, people act like I'm just not interested in what they are doing.

Let's get those passenger carrying quads in the air already... this ground travel is for the birds (emu's).

• Posts: 12,677
Cluso99 wrote: »
When we were there ~7 years ago, I don't recall traffic lights. Traffic went everywhere.

They had local guides near major roads and centres to help visitors cross the roads. You just walk across steadily, and they drive around you. Quite scary really
That's probably why they mostly ignore the lights. There not used to them being there. You're right that crossing takes a bit of getting used to.

• Posts: 294
rjo__ wrote: »

We need to get rid of turn signals as well. I got stopped in the middle of nowhere for not "signaling a turn." There was nobody with three miles to f'''ing signal. Nobody ever signals me... Constantly all day long, people act like I'm just not interested in what they are doing.

I'm pretty sure the law enforcement individual did not signal when they changed lanes to stop you, correct?

@Phil P.
Yeah, in Cali at least, if you stopped short and ended up the cross walk you would have got a ticket for that.

So, what happens where there are autonomous vehicles on the road and break a traffic law? Does the person riding in the vehicle get the ticket or does the manufacture of the vehicle get the ticket?
• Posts: 2,824
In California, it's only illegal to enter an intersection after the light turns red. If you are already past the line when it turns red, it's very difficult to have the ticket stand up in court.
• Posts: 489
In the US, there are two laws governing when you can enter a signalized intersection. Permissive and Restrictive. Most states are Permissive, meaning you can legally enter up to the point when the signal shows red. But in Restrictive states, you cannot legally enter after the end of the green, unless you are so close and cannot stop safely. The latter is much more subject to interpretation. The following states have Restrictive laws: Iowa, Michigan, Mississippi, Nebraska, New Jersey, Oregon, Virginia, Wisconsin and the District of Columbia.
Sapphire
• Posts: 1,956
edited November 2017
The whole point of yellow is to a) allow those who are too near the intersection to be able to safely pass, and b) warn the rest that they should stop because it's about to change to red. The yellow is timed such that a car that must pass still have time to do that before the crossing traffic gets the green.
If you can't enter *at all* on yellow, then there's no point in going green-yellow-red. Just switch from green directly to red, because it amounts to the same thing.
• Posts: 7,809
Yes, that "stop if it is safe to do so" is the stupidest thing I ever heard but apparently somehow, it is the law in many places. Why bother then with amber signals because I always thought amber was a warning and it was up to you to judge whether you had enough time to enter the intersection "before" a red light. So that "permissive" law sounds more like the sensible and practical law. If you enter the intersection when the light is red, then there is no question that you have judged poorly and are at fault. Now, if you are at fault "and speeding" then you should be doubly at fault. Otherwise, no fault, no "if it is safe to do so" rot.

Now don't get me started on roundabouts, they were designed to improve the flow of traffic but most people are too stupid to use them properly and now everyone stops to let just one car through coming from the right that is speeding but not even on or near the roundabout. Give way sign actually means give way to traffic ON the roundabout for everything to work properly. People even stop for cars coming from the opposite direction because they might turn (either way), but they might not indicate, or the indicator is no indicator of where they are going.

Now if every car around the city was driverless we could probably get there a lot faster with less lanes and no traffic lights.

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• Posts: 21,174
edited November 2017
Peter Jakacki ,
Now if every car around the city was driverless we could probably get there a lot faster with less lanes and no traffic lights.
You mean like this:

Intersection management for mixed autonomous and human operated vehicles:

Or this:

Autonomous Intersection Management with emergency vehicles

Looks kind of hairy scary to me.
• Posts: 3,366
In California, it's only illegal to enter an intersection after the light turns red. If you are already past the line when it turns red, it's very difficult to have the ticket stand up in court.

I'm pretty sure it's the same in WA state. The language of the law is almost identical: "Vehicle operators facing a steady circular yellow or yellow arrow signal are thereby warned that the related green movement is being terminated or that a red indication will be exhibited immediately thereafter when vehicular traffic shall not enter the intersection"

The law is stating that the red indication means no traffic shall enter the intersection. It doesn't say yellow cannot enter. (The exception is if there's pedestrian traffic in the intersection, in which case different laws apply.)

The laws saying "stop if it's safe to do so" is predicated on the belief that the yellow light is of sufficient duration to allow a car to come to a full and safe stop at the requisite distance, and assuming the appropriate road speed. Farther away you can still stop safely, and close you can't stop safely, and will likely be in or past the intersection when it turns red. I don't see the illogic in this. Makes perfect sense to me, assuming the yellow is timed properly. (If it's not, you can often fight it in court.)

As for who's liable for the infractions of self-driving car: Like it or not, YOU are. You're still the operator. Of course, you're free to sue the maker of the car.

• Posts: 3,366
Heater. wrote: »
Looks kind of hairy scary to me.

And pointless. Looks like Erco won't be driving his *completely manual* Corvair through that intersection any time soon.

Also looks like there are no pedestrian sidewalks in the future. Good to know.

• Posts: 22,044
edited November 2017
In Washington State, the Driver's Guide and the actual law appear to be at odds, then, with the Driver's Guide expressing the restrictive language:

"A steady yellow traffic light means the traffic light is about to change to red. You must stop if it is safe to do so."

This is what most drivers see and remember, rather than the wording of the Revised Code of Washington (RCW).

-Phil
Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
• Posts: 2,824
edited November 2017
Heater. wrote: »
Intersection management for mixed autonomous and human operated vehicles

Looks kind of hairy scary to me.

Agreed. The first video is very flawed actually. You would never see a line of 6 cars in the middle lane while the left and right lanes are empty. Humans are not that patient nor unselfish. The example does not clearly reflect actual human driving habits, so it's not really a demo, but an artificially generated reality to prove their point. Where I come from, we call that a "fail".
In the last segment when it is 100% autonomous, the lights are still cycling....why? If an autonomous car can go through a red light with a reservation, why wouldn't all the lights just be red if all cars are autonomous? You only need a green if a human driver shows up.

I have said it before and I will say it again. Self-driving cars should not be allowed on the road until human drivers are not allowed on the road. Self driving cars cannot anticipate the number one concern on the road today: unpredictable human drivers. Cameras on self driving cars need to be able to read driver expressions in other cars, recognize cell phones, make-up, or food in their hands, etc. to really make accurate decisions on the road. Same goes for the opposite. If I came to a stop sign at the same time opposite a driverless car, I would probably sit until it went because I wouldn't know if it was going to allow me to go first or not. Or, maybe I would just go, because I know it would do anything avoid an accident, so it would let me go first, lol.
• Posts: 8,011
I don't see a problem in sharing the road with self driving cars as long as they are programmed to obey the same traffic rules we are supposed to follow. Couldn't possibly be any worse than a lot of the drivers on the roads now....unless they are running Windows.
In science there is no authority. There is only experiment.
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• Posts: 337
Don M wrote: »
How many times have you had to stop at a light when there aren't any vehicles in the intersecting lanes and they have the in-ground proximity sensors? The light just changes. Drives me nuts.

Also the length of time that the turn lane light stays green... sometimes only gets a few cars through.

Seems like there could be a lot more logic built in to this that what they have now.

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• Posts: 3,366
In Washington State, the Driver's Guide and the actual law appear to be at odds, then, with the Driver's Guide expressing the restrictive language

Phil, I think they are congruent. The guide is taking a subjective approach, centering on common sense rather than the specifics of the law. The code can say the yellow is a warning the signal is about to turn red, and it's entering the intersection on a red light that prohibited. Other types of misbehavior (gunning it to get through) are separately illegal, and the guide is simplifying all those into a "you must stop if it's safe to do so." In the end, it's true that you must stop if it's safe. That's what yellow lights are timed for.

On the safety of driverless cars: It's already been demonstrated that they are safer among human drivers than human drivers are among other human drivers. It's true that the accidents they are involved in are related to unpredictable human behavior, but that same behavior applies to all types of drivers, carbon or silicon based. It's most common for driverless cars to get hit because humans are gawking them (rotating lidars are so much fun!) rather than the road. A little less common are accidents stemming from not being as aggressive as human drivers -- they too closely follow the law. This is a known defect they've been working on for some time now.

On who goes at an intersection: Apart from established law of who goes first at uncontrolled intersections, much of the AI involves tens of thousands (if not more) insurance claims about which scenarios cause the accidents. The average human driver lacks this database, and is inherently the less safe driver.

Driving safety isn't really the big problem anyway. The overriding concern is the legal aspects for when the inevitable accidents do occur. The biggest problem is whether someone like Google will be hauled into court every time a car using their technology is involved in an accident. Lawyers always go after the deepest pockets. The laws of every state have to be revised to provide a framework of liability. That will take many years., and no doubt some states will take longer to settle these matters. That leaves consumers in a legally precarious place.
• Posts: 1,956
edited November 2017
When I drive, I read the traffic.. and sometimes I see that vehicle A will have to pass pedestrian B at a time X when my car will be at a point where vehicle C will create problems for vehicle A because vehicle C will meet me. So what do I do? I slow down, or sometimes I speed up, to adjust the timing so this doesn't happen at X. Everything goes smoothly.
I wonder if those self-driving cars can do that.
Admittedly, there are people who can't do it either. Not even the simpler types of reading traffic. There was a funny one the other day:
```   |x    |
|x    |
----x    |
x x x -Y |
x x x  x |
----x  x |
|x  x |
|x  M |------
|X- R
|x  x |------
|x  x |
|   x |
|   x |
|   x |
```

Right side driving - traffic flowing 'up' on the right side, and 'down' on the left side. I was following the traffic, planning to go left (where car 'Y' is turning left). My car is M. I passed the road that's going to the right, and there was a gap behind me. I had noticed car X which wanted to turn to (his) left, into that road. Space behind me. But car R decided to follow me, even though he could as well as I did see the traffic in front, with car Y waiting to go left. But he ignored that, and followed, stopping behind me - and blocking X from turning. X, then, stopped all the traffic behind him, which meant that Y was blocked from going left, so that we were all stuck and nobody could move. That took some minutes before someone managed to wriggle their car enough to create an opening ahead.
I was just astonished that R didn't see what would happen. If he had just waited one car length further back then everything would flow nicely.
• Posts: 8,011
That's called gridlock, and I see it more often than I should in downtown areas. Too many brain dead drivers on the roads.
In science there is no authority. There is only experiment.
Life is unpredictable. Eat dessert first.
• Posts: 1,253
edited November 2017
kwinn wrote: »
I don't see a problem in sharing the road with self driving cars as long as they are programmed to obey the same traffic rules we are supposed to follow. Couldn't possibly be any worse than a lot of the drivers on the roads now....unless they are running Windows.

ROFLOL
• Posts: 21,174
Problem is they run Android and iOS. They are so busy checking Facebook and such they pay no attention to the road or traffic.
• Posts: 3,366
Tor wrote: »
I wonder if those self-driving cars can do that.

They can do that.

Google's Waymo spinoff just passed its four million mile mark, nearly all of which were on public roads. That's far more than a person will ever drive in several lifetimes. The cars have been in slightly fewer accidents than the average for human drivers, but unlike human accidents, , they've been minor. Human accidents are more likely to be at higher speed, and involve serious injury and a complete totaling of the vehicle. One injury accident of a Google car was the fault of a human driver who was being inattentive at an intersection.

I take a pragmatic approach to self-driving cars. In a world where traffic fatalities are going up because of distracted driving, they are likely to bring down traffic deaths. They also are extremely useful for younger and older drivers, the age groups that cause the most accidents. You're more likely to rest assured your 85 year old grandma will get to her shopping every week in a self-driving car. At that age, she might not even be able to drive - at least safely - and a self-driving car gives back her autonomy. She can live a more enriched life taking care of herself. That's worth something.
• Posts: 22,044
You're more likely to rest assured your 85 year old grandma will get to her shopping every week in a self-driving car.
Assuming she can figure out how to enter her destination in the console!

-Phil
Perfection is achieved not when there is nothing more to add, but when there is nothing left to take away. -Antoine de Saint-Exupery
• Posts: 21,174
Gary Kasparov gave an interesting talk on his view of AI, self driving vehicles etc recently.

Given that he was the first world champion chess player beaten by a computer he was very optimistic about it all.

Kasparov told a great tale about elevator operators in New York.

Seems that in the early 1990's there were 17000 elevator operators in New York. Despite the fact that elevators were fully automatic, self driving if you like, with destination buttons and safety features, people did not trust them. They wanted a human elevator operator.

Until, one day the elevator operators went on strike. Thinking they were not paid enough. Soon everyone manned up, took the risk, and rode the elevator by themselves. Rather than not get to work or have walk up 20 floors of stairs.

That was the end of the elevator operator profession !

DEF CON 25 - Garry Kasparov - The Brain's Last Stand:

It's a fun presentation worth watching.

• Posts: 1,956
I still doubt self-driving cars can do more than following traffic rules. From what has been reported about accidents (not caused by self-driving cars breaking any rules) it sounds like that's what they do. I very much doubt they can imagine what-if cases several seconds into the future that does not directly involve their own vehicle. Can they see that if they continue at their current speed, that its vehicle would some seconds later prevent another car from doing an evasive maneuvre if that man over there's dog suddenly decides to move a leash's length into the road? Because that's the kind of things I have to consider every single day when I drive to and from work. Not to mention evaluating the road's condition (snow and ice) of that day and place, and how that affects what other cars do.
• Posts: 490
Traffic lights are controlled by a central computer. The light timing is changed at different times of the day depending on rush hour, weekends, etc. via modem to the control box at the light. Most lights are red twice as long as they are green for example a light maybe red for 1.5 minutes and green only 45 seconds. The purpose is to hold the traffic back so it doesn't bottle neck somewhere down the road. Loops in the ground have been replace with cameras. They detect if cars are present but have a short term memory storage to review an accident.
• Posts: 490
Once a light turns yellow any loop or camera detectors are locked out. So you want to be on the loop detector before the crossing traffic turns yellow.
• Posts: 21,174
edited November 2017
DigitalBob,
Traffic lights are controlled by a central computer. The light timing is changed at different times of the day depending on rush hour, weekends, etc. via modem to the control box at the light. Most lights are red twice as long as they are green for example a light maybe red for 1.5 minutes and green only 45 seconds. The purpose is to hold the traffic back so it doesn't bottle neck somewhere down the road. Loops in the ground have been replace with cameras. They detect if cars are present but have a short term memory storage to review an accident.
Except, in Scandinavia and, now I find, California.

Most of it is based on 1980's technology. Even if the hardware and processors have been upgraded over time the system is the same.

For example: In California it's impossible to get most traffic controllers to tell you which lanes it has detected a vehicle in. It knows there is something coming from some direction but that's it.

Why? Because all the loop detectors across the lanes are physically wired together in an OR fashion and that is all the controller knows. WTF?

Don't ask, I have been sucked into the traffic light thing far too often over the past two decades.