Red light cameras = more traffic congestion

[fromderinside]

You don't need to see my personal testimony again. However you need to reread the 'article' you posted. Its a set of personal experiments supported by
1. pesonal testimony
2 models

It is not refereed.

It's also not wrong, and not the only similar result.

Test it yourself.

Or don't. I'm happy for people who live a long way away to remain ignorant of the harm they do to themselves and their neighbours; I don't have the energy to try to save the world from stupid false beliefs. There are just too many of them.

Have you ever driven past LAX between 7 and 10 AM on Tuesday after coming from west valley on 101, transitioning to the 405, getting past the 10, then the 110 and 710? Friday's the worst from about 2:30 to about 7 PM. We're talking about three of the top five congested freeways in America. No accidents. One ticket, 25 years.

OK so I have vascular and heat problems.

Just wanted to say that to one who is spouting authority who probably has no idea what its actually like.

I'm up here in speederfundus now loving it.

 

[barbos]

If you are driving in LA during rush afternoon or morning (about four hours each) and you leave a descent gap for traffic, even though you are driving in a pack going about three miles per decade, you are the one causing traffic problems.

This is exactly and completely wrong.

It is very widely and passionately believed to be true; and some people are prepared to engage in lethal violence because of this false belief; but that doesn't make it true. You can say the same of Islam.

Leaving a decent gap - sufficient for others to merge in front of you - in crawling freeway traffic, actually increases the throughput of the road; it only takes a minority of drivers doing this to have a significant effect.

http://www.smartmotorist.com/traffic-and-safety-guideline/traffic-jams.html

Not about gap but I used to drive the same road and after a while I learned how to pace myself to get under the green on the next intersection, obviously it involved moving a bit slower than the traffic and leaving a rather large gap. One day I was doing it successfully, saving brake pads and fuel. The guy behind me lost patience and overtook me, I was glad he did not shoot me. Needless to say he stopped at the next intersection and I did not, I got in time for green light and him passing intersection. In any case he probably saved few seconds.

 

[bilby]

It's also not wrong, and not the only similar result.

Test it yourself.

Or don't. I'm happy for people who live a long way away to remain ignorant of the harm they do to themselves and their neighbours; I don't have the energy to try to save the world from stupid false beliefs. There are just too many of them.

Have you ever driven past LAX between 7 and 10 AM on Tuesday after coming from west valley on 101, transitioning to the 405, getting past the 10, then the 110 and 710? Friday's the worst from about 2:30 to about 7 PM. We're talking about three of the top five congested freeways in America. No accidents. One ticket, 25 years.

OK so I have vascular and heat problems.

Just wanted to say that to one who is spouting authority who probably has no idea what its actually like.

I'm up here in speederfundus now loving it.

Oddly, the laws of physics are not suspended for your pet hates.

I don't give a flying fuck if you have driven on the highway to hell at 6:66pm every Thursday. If you try to stop others from getting in front of you on the highway, then you are part of the problem.

And reality doesn't give a shit about your beliefs on the matter.

Think about it; test it for yourself; research it online - plenty of studies have been done.

Or stick with your stupid and unsupported opinions. I just don't care anymore.

 

[Nice Squirrel]

There is nothing unreasonable about red light cameras.

On the other hand, you may have a problem with corruption and incompetence among your myriad local governments that can't even do something as simple as program the traffic lights.

...Plus quite a few drivers who are either impatient or don't know the road rules, and try to beat the red light.

The driverless car revolution can't come soon enough--most of the problems associated with human drivers will be become moot.

There's nothing wrong with the concept of red light cameras. In practice, though, fixed-location traffic enforcement is about exploiting something wrong with the location, not about safety.

Especially when nothing is physically done to improve safety.

 

[T.G.G. Moogly]

Have you ever driven past LAX between 7 and 10 AM on Tuesday after coming from west valley on 101, transitioning to the 405, getting past the 10, then the 110 and 710? Friday's the worst from about 2:30 to about 7 PM. We're talking about three of the top five congested freeways in America. No accidents. One ticket, 25 years.

OK so I have vascular and heat problems.

Just wanted to say that to one who is spouting authority who probably has no idea what its actually like.

I'm up here in speederfundus now loving it.

Oddly, the laws of physics are not suspended for your pet hates.

I don't give a flying fuck if you have driven on the highway to hell at 6:66pm every Thursday. If you try to stop others from getting in front of you on the highway, then you are part of the problem.

And reality doesn't give a shit about your beliefs on the matter.

Think about it; test it for yourself; research it online - plenty of studies have been done.

Or stick with your stupid and unsupported opinions. I just don't care anymore.

Years ago I moved from Pittsburgh PA to El Paso TX. Surprisingly my car insurance just about doubled. When I asked my insurer why I was told it was just because of the area.

What this thread clearly demonstrates is that if you live in an area where drivers are aggressive, like to run red lights and otherwise drive illegally then red light cameras will be problematic. This, however, is simply indicative of a larger problem with the subject population, which nicely explains why there would also be a problem with how these cameras are programmed and administered.

So in the end the fact is that sometimes you will have a greater number of stupid people living in one place, many of whom will also drive cars. Nothing mysterious about that.

Incidentally, there's a section of highway I drive regularly which has crosswalks at every intersection with those digital counters. So you can know exactly when the light will go from green to yellow. Oddly it's not a problem for me. It neither causes me to speed up or slow down, just gives me more information so I can drive even more safely.

 

[fromderinside]

Have you ever driven past LAX between 7 and 10 AM on Tuesday after coming from west valley on 101, transitioning to the 405, getting past the 10, then the 110 and 710? Friday's the worst from about 2:30 to about 7 PM. We're talking about three of the top five congested freeways in America. No accidents. One ticket, 25 years.

OK so I have vascular and heat problems.

Just wanted to say that to one who is spouting authority who probably has no idea what its actually like.

I'm up here in speederfundus now loving it.

Oddly, the laws of physics are not suspended ...

Or stick with your ... opinions. I just don't care anymore.

Apparently the laws of physics give way to the laws of human behavior to the benefit (according the source listed below) of greater traffic flow.

There is also a wild card in the mix of what determines capacity—driver behavior. Research has shown that drivers familiar with routinely congested roadways space themselves closer together than drivers on less congested roadways. This leads to an increase in the amount of traffic that can be handled.

There's trove of more practical examples and data in this 2005 publication than the musings of some aeronautical engineer, probably from Boeing the company I worked for as a humane engineering research scientist, who showed off in a blog.

From: Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/chapter2.htm#footer12 in Traffic Congestion and Reliability:Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/index.htm

Geez. An observation .... in a report .... summarizing other data from experiments and papers .... not containing personal experiments ..... I wonder why bilby didn't cite this ....

See I can do it too without all the personal characterizations .....

The problem in LA is that driver demand exceeds capacity by so much that it would be almost impossible to make up the difference with build baby build. For instance there are four more lanes over the hill on 405 between the 101 and the 10 than were there when I retired in 2003 with a net decrease in travel speeds with concomitant increased congestion. Who'da thunk.

Different cities, different driving conditions, different perspectives, different consequences.

Oh. By the way. If one is interested in safety and not collections one might consider equipping cars with systems that respond to approaching intersection signals so the idiots who are dreaming, texting, zoning, speeding, are noisily alerted to same. It will actually decrease accidents collisions, run downs and the like.

 

[bilby]

Oddly, the laws of physics are not suspended ...

Or stick with your ... opinions. I just don't care anymore.

Apparently the laws of physics give way to the laws of human behavior to the benefit (according the source listed below) of greater traffic flow.

There is also a wild card in the mix of what determines capacity—driver behavior. Research has shown that drivers familiar with routinely congested roadways space themselves closer together than drivers on less congested roadways. This leads to an increase in the amount of traffic that can be handled.

There's trove of more practical examples and data in this 2005 publication than the musings of some aeronautical engineer, probably from Boeing the company I worked for as a humane engineering research scientist, who showed off in a blog.

From: Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/chapter2.htm#footer12 in Traffic Congestion and Reliability:Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/index.htm

Geez. An observation .... in a report .... summarizing other data from experiments and papers .... not containing personal experiments ..... I wonder why bilby didn't cite this ....

See I can do it too without all the personal characterizations .....

The problem in LA is that driver demand exceeds capacity by so much that it would be almost impossible to make up the difference with build baby build. For instance there are four more lanes over the hill on 405 between the 101 and the 10 than were there when I retired in 2003 with a net decrease in travel speeds with concomitant increased congestion. Who'da thunk.

Different cities, different driving conditions, different perspectives, different consequences.

Oh. By the way. If one is interested in safety and not collections one might consider equipping cars with systems that respond to approaching intersection signals so the idiots who are dreaming, texting, zoning, speeding, are noisily alerted to same. It will actually decrease accidents collisions, run downs and the like.

There is, as far as I can see, not a single thing in the paper you linked to that even hints at the assertion "If you are driving [...] and you leave a descent gap for traffic, [...] you are the one causing traffic problems" has the slightest connection to reality.

It is, was and remains complete bollocks - not just wrong, but dangerously and stupidly wrong.

I have shown this; your response is barely coherent, and where it is coherent is irrelevant anecdotes and links to unrelated stuff about managing congestion through highway design and strategic planning, with no mention whatever of the appropriate driver behaviour with regards to maintaining a suitable separation from the car in front.

Either put up an argument in support of your claim:

If you are driving in LA during rush afternoon or morning (about four hours each) and you leave a descent gap for traffic, even though you are driving in a pack going about three miles per decade, you are the one causing traffic problems.

Or withdraw it.

 

[fromderinside]

Oddly, the laws of physics are not suspended ...

Or stick with your ... opinions. I just don't care anymore.

Apparently the laws of physics give way to the laws of human behavior to the benefit (according the source listed below) of greater traffic flow.

There is also a wild card in the mix of what determines capacity—driver behavior. Research has shown that drivers familiar with routinely congested roadways space themselves closer together than drivers on less congested roadways. This leads to an increase in the amount of traffic that can be handled.

From: Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/chapter2.htm#footer12 in Traffic Congestion and Reliability:Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/index.htm

Geez. An observation .... in a report .... summarizing other data from experiments and papers .... not containing personal experiments ..... I wonder why bilby didn't cite this ....

See I can do it too without all the personal characterizations .....

There's trove of more practical examples and data in this 2005 publication than the musings of some aeronautical engineer, probably from Boeing the company I worked for as a humane engineering research scientist, who showed off in enthusiast magazine.

The problem in LA is that driver demand exceeds capacity by so much that it would be almost impossible to make up the difference with build baby build. For instance there are four more lanes over the hill on 405 between the 101 and the 10 than were there when I retired in 2003 with a net decrease in travel speeds with concomitant increased congestion. Who'da thunk.

Different cities, different driving conditions, different perspectives, different consequences.

Oh. By the way. If one is interested in safety and not collections one might consider equipping cars with systems that respond to approaching intersection signals so the idiots who are dreaming, texting, zoning, speeding, are noisily alerted to same. It will actually decrease accidents collisions, run downs and the like.

There is, as far as I can see, not a single thing in the paper you linked to that even hints at the assertion "If you are driving [...] and you leave a descent gap for traffic, [...] you are the one causing traffic problems" has the slightest connection to reality.

It is, was and remains complete bollocks - not just wrong, but dangerously and stupidly wrong.

I have shown this; your response is barely coherent, and where it is coherent is irrelevant anecdotes and links to unrelated stuff about managing congestion through highway design and strategic planning, with no mention whatever of the appropriate driver behaviour with regards to maintaining a suitable separation from the car in front.

Either put up an argument in support of your claim:

If you are driving in LA during rush afternoon or morning (about four hours each) and you leave a descent gap for traffic, even though you are driving in a pack going about three miles per decade, you are the one causing traffic problems.

Or withdraw it.

I bolded it. If you don't drive close up during rush hour you are limiting access for others to the freeway. You may be part of the problem. Drivers familiar with routinely congested roadways space themselves closer together than drivers on less congested highways ...result increasing amount of traffic that can be handled ... seems a pretty good match with if you don't you are causing problems.

There may even be a bit in there about leaving space on multi-lane freeways during congestion lead to more accidents due to drivers taking advantage of lane changes to gain position on the freeway. After all lane changing requires more information processing by drivers implying more risks are likely to be taken. I didn't bother to find it so we'll let that one just wait for me to read another authoritative, not conversational, article.

No fluid dynamics here bilby. Just good old human factors principles. Situation awareness certainly isn't something normal engineers attend. Hell they have to be told that if dials don't go in the expected direction plots, drivers, tend to make mistakes. Oh year and Fuck Golden arm arguments even though 'drivers familiar with' might be so construed.

Well I certainly won't take what you wrote about the articles I referenced since you didn't even see the bit I had to bold to illustrate the error in the leaving space personal observation you posted.

 

[bilby]

Oddly, the laws of physics are not suspended ...

Or stick with your ... opinions. I just don't care anymore.

Apparently the laws of physics give way to the laws of human behavior to the benefit (according the source listed below) of greater traffic flow.

There is also a wild card in the mix of what determines capacity—driver behavior. Research has shown that drivers familiar with routinely congested roadways space themselves closer together than drivers on less congested roadways. This leads to an increase in the amount of traffic that can be handled.

From: Traffic Congestion and Reliability: Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/chapter2.htm#footer12 in Traffic Congestion and Reliability:Trends and Advanced Strategies for Congestion Mitigation http://www.ops.fhwa.dot.gov/congestion_report/index.htm

Geez. An observation .... in a report .... summarizing other data from experiments and papers .... not containing personal experiments ..... I wonder why bilby didn't cite this ....

See I can do it too without all the personal characterizations .....

There's trove of more practical examples and data in this 2005 publication than the musings of some aeronautical engineer, probably from Boeing the company I worked for as a humane engineering research scientist, who showed off in enthusiast magazine.

The problem in LA is that driver demand exceeds capacity by so much that it would be almost impossible to make up the difference with build baby build. For instance there are four more lanes over the hill on 405 between the 101 and the 10 than were there when I retired in 2003 with a net decrease in travel speeds with concomitant increased congestion. Who'da thunk.

Different cities, different driving conditions, different perspectives, different consequences.

Oh. By the way. If one is interested in safety and not collections one might consider equipping cars with systems that respond to approaching intersection signals so the idiots who are dreaming, texting, zoning, speeding, are noisily alerted to same. It will actually decrease accidents collisions, run downs and the like.

There is, as far as I can see, not a single thing in the paper you linked to that even hints at the assertion "If you are driving [...] and you leave a descent gap for traffic, [...] you are the one causing traffic problems" has the slightest connection to reality.

It is, was and remains complete bollocks - not just wrong, but dangerously and stupidly wrong.

I have shown this; your response is barely coherent, and where it is coherent is irrelevant anecdotes and links to unrelated stuff about managing congestion through highway design and strategic planning, with no mention whatever of the appropriate driver behaviour with regards to maintaining a suitable separation from the car in front.

Either put up an argument in support of your claim:

If you are driving in LA during rush afternoon or morning (about four hours each) and you leave a descent gap for traffic, even though you are driving in a pack going about three miles per decade, you are the one causing traffic problems.

Or withdraw it.

I bolded it. If you don't drive close up during rush hour you are limiting access for others to the freeway. You may be part of the problem. Drivers familiar with routinely congested roadways space themselves closer together than drivers on less congested highways ...result increasing amount of traffic that can be handled ... seems a pretty good match with if you don't you are causing problems.

There may even be a bit in there about leaving space on multi-lane freeways during congestion lead to more accidents due to drivers taking advantage of lane changes to gain position on the freeway. After all lane changing requires more information processing by drivers implying more risks are likely to be taken. I didn't bother to find it so we'll let that one just wait for me to read another authoritative, not conversational, article.

No fluid dynamics here bilby. Just good old human factors principles. Situation awareness certainly isn't something normal engineers attend. Hell they have to be told that if dials don't go in the expected direction plots, drivers, tend to make mistakes. Oh year and Fuck Golden arm arguments even though 'drivers familiar with' might be so construed.

Well I certainly won't take what you wrote about the articles I referenced since you didn't even see the bit I had to bold to illustrate the error in the leaving space personal observation you posted.

So your argument is "I believe, therefore I am right".

Got it.

By the way, if getting closer to the car in front improved throughput, then the maximum throughput of a highway would be when all the cars are touching, bumper to bumper.

If you can't see how that assumption is flawed, then there's no hope for you.

 

[fromderinside]

So your argument is "I believe, therefore I am right".

Got it.

By the way, if getting closer to the car in front improved throughput, then the maximum throughput of a highway would be when all the cars are touching, bumper to bumper.

If you can't see how that assumption is flawed, then there's no hope for you.

Geez. Light brigade principles? Ignore the facts presented and keep charging with the denial. Better yet, Egyptian principle of deNile.

Study shows experienced congestion drivers close up resulting in measured increases in throughput and you go 'give me my physic'.

How can I explain your posts any other way. You have this engineer who runs a few informal 'experiments' and sees wha t he wants to see, probably on a two lane highway, there are a lot of those up there in Seattle - Yeah, I did visit the place quite often as a human engineering consultant from hinterlands of McDonnell Douglas Land so I understand Fluid's perspective - engineers who think engineer (machine) for everything.

Its people like that who designed the F 57 that kept crashing in Laos until HFE studied its design and found engineers designed wings for forward and back while pilots thought high speed low speed. Pilots pull back lower speed leads to wings back and plane crashes. Over and over and over again. Its gotta be physics when its run by humans and bad things happen. Since cars aren't coupled like fluids and cars are driven by humans why expect a physics answer when humans can be expected to adjust to gain advantage. Besides cars in congested situations are moving slower than cars in normal open highway conditions so why assert increase space between cars at lower speeds.

Seems to me I'm not the one drinking Kool Aid. You just got caught up in your individual observation study by an engineer and bit down. Time to let go.

You're going to ludicrous analogy of if some is good all is better nonsense. It's obvious to all that congestion means slower and slower means less gap is probably better so more cars can share same amount of highway fairly safely, oh, and less gap between cars discourages lane switching on multi-lane highways.

Not belief. Facts. Documented.

 

[bilby]

So your argument is "I believe, therefore I am right".

Got it.

By the way, if getting closer to the car in front improved throughput, then the maximum throughput of a highway would be when all the cars are touching, bumper to bumper.

If you can't see how that assumption is flawed, then there's no hope for you.

Geez. Light brigade principles? Ignore the facts presented and keep charging with the denial. Better yet, Egyptian principle of deNile.

Study shows experienced congestion drivers close up resulting in measured increases in throughput and you go 'give me my physic'.

How can I explain your posts any other way. You have this engineer who runs a few informal 'experiments' and sees wha t he wants to see, probably on a two lane highway, there are a lot of those up there in Seattle - Yeah, I did visit the place quite often as a human engineering consultant from hinterlands of McDonnell Douglas Land so I understand Fluid's perspective - engineers who think engineer (machine) for everything.

Its people like that who designed the F 57 that kept crashing in Laos until HFE studied its design and found engineers designed wings for forward and back while pilots thought high speed low speed. Pilots pull back lower speed leads to wings back and plane crashes. Over and over and over again. Its gotta be physics when its run by humans and bad things happen. Since cars aren't coupled like fluids and cars are driven by humans why expect a physics answer when humans can be expected to adjust to gain advantage. Besides cars in congested situations are moving slower than cars in normal open highway conditions so why assert increase space between cars at lower speeds.

Seems to me I'm not the one drinking Kool Aid. You just got caught up in your individual observation study by an engineer and bit down. Time to let go.

You're going to ludicrous analogy of if some is good all is better nonsense. It's obvious to all that congestion means slower and slower means less gap is probably better so more cars can share same amount of highway fairly safely, oh, and less gap between cars discourages lane switching on multi-lane highways.

Not belief. Facts. Documented.

If it's obvious that congestion means slower, how can it not be equally obvious that closer means slower - or do you not know the meaning of the word 'congestion'?

Hint - it means when the cars can't move much, because they are all too close together.

You are talking nonsense.

Throughput is not a linear function of traffic density - it is zero at zero cars on the road, and it is also zero when cars occupy 100% of the space.

Once traffic density exceeds the optimum, further increases in density reduce throughput.

Congestion is the word we use to describe traffic density above that optimum level. That's what congestion IS. Anything that reduces density in congested traffic will increase throughput.

This is not about the one article I linked to first - I chose it because it provides an easy primer on the subject for the hard of thinking.

Did you read any of the articles at my later link to Google Scholar?

I didn't think so.

You are way off in Dunning-Kruger land here. You probably haven't seriously considered the dynamics of throughput on highways, nor it's similarities with other throughput issues (including in production lines, pipelines, and even packet queuing on computer networks) until this thread came up, and you decided that your having taken part in LA traffic jams was grounds to consider yourself an expert.

Well, it isn't.

I made a living out of my understanding of process flow and throughput for over a decade. It is very obvious to me that much of the science is directly applicable to highway traffic, particularly in congested conditions. And that many of the intuitive responses to low throughput that are counterproductive in a manufacturing facility are equally wrong and counterproductive in traffic. High load density causes congestion and reduces throughput; and this can be alleviated by leaving enough 'gap' to handle the inevitable excursions from perfection.

You can demonstrate that I am wrong, by showing me a road where traffic consistently moves at more than 80% of the speed limit while bumper to bumper. I won't hold my breath.


ETA - I notice you remain convinced that discouraging lane changes is a good thing. It's not. It's a very bad thing, both for traffic flow and for safety. You need to drop the Neanderthal idea that the bit of road in front of your car is your property, and that letting someone merge in front of you is somehow an insult to your manhood. That false belief is harming you and others.

 

[TSwizzle]

Have you ever driven past LAX between 7 and 10 AM on Tuesday after coming from west valley on 101, transitioning to the 405, getting past the 10, then the 110 and 710? Friday's the worst from about 2:30 to about 7 PM. We're talking about three of the top five congested freeways in America. No accidents. One ticket, 25 years.

The 405 is a parking lot most of the day I think. I don't travel on the 405 very often, I try to avoid it. And when the 105 opened it was great for getting from the SFV to LAX. Hop on the 5 south through Downtown, bit of a bottleneck there, particularly if the Dodgers or something going on at Staples Center, then 110 to the 105 to LAX. The traffic moved at a fair clip most of the time. A couple of years ago, the carpool lanes on the 105 were changed to "Express Lanes" and there is a fee involved. So now you are stuck in traffic and the Express Lanes are hardly used. It has gotten so bad, that when going back to the SFV from LAX, I take the 405 north, 118 and back on the 5 south and it is not too bad. The slowdown appears to be mostly on the hill at the Getty where cars slowdown because of the hill.

 

[fromderinside]

Not belief. Facts. Documented.

If it's obvious that congestion means slower, how can it not be equally obvious that closer means slower - or do you not know the meaning of the word 'congestion'?

Hint - it means when the cars can't move much, because they are all too close together.

Drivers familiar with congestion chose to drive closer than they would on open highway. They do not drive like inexperienced drivers reacting to road conditions because 'gee there's a bunch of cars going slow ahead'. They are using awareness of situation to adjust their normal behavior for current conditions. Usually experienced congestion drivers continue to drive near normal speeds only closer to the car ahead than would be normal on open highway. They are not reacting to threat. They are using conditions to their advantage knowing its becoming congested so drivers will be using less accelerator, therefore one'll be less likely to have to react to a sudden change, therefore one will be safer than they would be if their minds were allowed to wander as drivers often do on open freeway.

These are all facts. Drivers familiar with congestion understand and practice congestion driving knowing most others with him are doing like wise. They begin to act cooperatively rather than reactive 'their all out to get me' cowboys. The driving closer together reflects this cooperative behavior since most others are, even though they may have a bit of open space, acting as if the roads were congested.

Purposeful rather than reactive. Instead of "oh shit what's she doing" its "OK its time for test operate test exit" group behavior.

 

[fromderinside]

Have you ever driven past LAX between 7 and 10 AM on Tuesday after coming from west valley on 101, transitioning to the 405, getting past the 10, then the 110 and 710? Friday's the worst from about 2:30 to about 7 PM. We're talking about three of the top five congested freeways in America. No accidents. One ticket, 25 years.

The 405 is a parking lot most of the day I think. I don't travel on the 405 very often, I try to avoid it. And when the 105 opened it was great for getting from the SFV to LAX. Hop on the 5 south through Downtown, bit of a bottleneck there, particularly if the Dodgers or something going on at Staples Center, then 110 to the 105 to LAX. The traffic moved at a fair clip most of the time. A couple of years ago, the carpool lanes on the 105 were changed to "Express Lanes" and there is a fee involved. So now you are stuck in traffic and the Express Lanes are hardly used. It has gotten so bad, that when going back to the SFV from LAX, I take the 405 north, 118 and back on the 5 south and it is not too bad. The slowdown appears to be mostly on the hill at the Getty where cars slowdown because of the hill.

Been a while but I recognize you probably live in east SF valley. Us west SF valley types go to the 210 thence to the 605 to the 105 then west to LAX. Actually, if I get up early I just take 101 from Topanga on ramp to 405 to Century. Get there in about 25 minutes. What the hey. Watch the boats coming out of the Marina if I have time. Then take Lincoln south until it merges with Sepulveda to Century.

 

[bilby]

If it's obvious that congestion means slower, how can it not be equally obvious that closer means slower - or do you not know the meaning of the word 'congestion'?

Hint - it means when the cars can't move much, because they are all too close together.

Drivers familiar with congestion chose to drive closer than they would on open highway.

Yes. But doing so is counterproductive, even if they don't realise it.

They do not drive like inexperienced drivers reacting to road conditions because 'gee there's a bunch of cars going slow ahead'. They are using awareness of situation to adjust their normal behavior for current conditions.

Which would be a good thing, if only their intuitive response was not completely the wrong thing to do.

Usually experienced congestion drivers continue to drive near normal speeds only closer to the car ahead than would be normal on open highway.

Indeed. Until the traffic forces them to slow down; which they then think is totally unrelated to their failure to leave sufficient space.

They are not reacting to threat.

I never suggested they were

They are using conditions to their disadvantage knowing its becoming congested

FTFY

so drivers will be using less accelerator, therefore one'll be less likely to have to react to a sudden change,

They are objectively wrong, if that's their belief; but even if they were correct, their response would still be counterproductive

therefore one will be safer than they would be if their minds were allowed to wander as drivers often do on open freeway.

Nobody is suggesting that not concentrating on the road is a good idea under any conditions. If your mind tends to wander when you are driving, you need to stop driving

These are all facts.

Prove it.

Drivers familiar with congestion understand and practice congestion driving knowing most others with him are doing like wise.

Not at all. Very few drivers understand congestion at all. Participating is not understanding. Intuition is a poor guide to reality

They begin to act cooperatively rather than reactive 'their all out to get me' cowboys. The driving closer together reflects this cooperative behavior since most others are, even though they may have a bit of open space, acting as if the roads were congested.

Which would be great, if they weren't acting in a way that is directly counterproductive. Cooperation towards an undesirable end due to a lack of understanding is not laudable.

Purposeful rather than reactive. Instead of "oh shit what's she doing" its "OK its time for test operate test exit" group behavior.

Purpose is great - unless your grasp of cause and effect is back to front.

By closing the gaps, drivers 'solve' the non-problems of other drivers making lane changes, and of empty sections of road being available; but are acting counter to the solution of the actual problem - that of improving the throughput of the road.

 

[TSwizzle]

The 405 is a parking lot most of the day I think. I don't travel on the 405 very often, I try to avoid it. And when the 105 opened it was great for getting from the SFV to LAX. Hop on the 5 south through Downtown, bit of a bottleneck there, particularly if the Dodgers or something going on at Staples Center, then 110 to the 105 to LAX. The traffic moved at a fair clip most of the time. A couple of years ago, the carpool lanes on the 105 were changed to "Express Lanes" and there is a fee involved. So now you are stuck in traffic and the Express Lanes are hardly used. It has gotten so bad, that when going back to the SFV from LAX, I take the 405 north, 118 and back on the 5 south and it is not too bad. The slowdown appears to be mostly on the hill at the Getty where cars slowdown because of the hill.

Been a while but I recognize you probably live in east SF valley. Us west SF valley types go to the 210 thence to the 605 to the 105 then west to LAX. Actually, if I get up early I just take 101 from Topanga on ramp to 405 to Century. Get there in about 25 minutes. What the hey. Watch the boats coming out of the Marina if I have time. Then take Lincoln south until it merges with Sepulveda to Century.

I sometimes have to get to the West Side from Encino, I take the 101 to the 405 and there is a bottleneck trying to make that transition from the 101 onto the 405, plus the general slowdown as you try to get over the hill. Downhill clips along nicely. Traffic in LA is brutal. I think they do it on purpose.

 

[Loren Pechtel]

If it's obvious that congestion means slower, how can it not be equally obvious that closer means slower - or do you not know the meaning of the word 'congestion'?

Hint - it means when the cars can't move much, because they are all too close together.

You are talking nonsense.

Throughput is not a linear function of traffic density - it is zero at zero cars on the road, and it is also zero when cars occupy 100% of the space.

Once traffic density exceeds the optimum, further increases in density reduce throughput.

Congestion is the word we use to describe traffic density above that optimum level. That's what congestion IS. Anything that reduces density in congested traffic will increase throughput.

No. Congestion is the word we use to describe traffic density sufficient to slow the flow of traffic.

ETA - I notice you remain convinced that discouraging lane changes is a good thing. It's not. It's a very bad thing, both for traffic flow and for safety. You need to drop the Neanderthal idea that the bit of road in front of your car is your property, and that letting someone merge in front of you is somehow an insult to your manhood. That false belief is harming you and others.

Lane changes in heavy traffic slow things down and are a risk. They should be minimized.

 

[bilby]

ETA - I notice you remain convinced that discouraging lane changes is a good thing. It's not. It's a very bad thing, both for traffic flow and for safety. You need to drop the Neanderthal idea that the bit of road in front of your car is your property, and that letting someone merge in front of you is somehow an insult to your manhood. That false belief is harming you and others.

Lane changes in heavy traffic slow things down and are a risk.

Because (and ONLY because) fuckwits try to prevent them from happening

They should be minimized.

No. They occur because people want to change lanes. Trying to stop someone from doing that causes FAR more of a delay than making it easy for them; So for your hypothesis to carry any weight at all, you need to show that people changing lanes where a large gap has been left causes more delay; or that most lane changes are made on a whim by drivers who see no advantage in being in a different lane, but just felt like changing for pure entertainment.

People change lanes to get to their exit - blocking those people is a very good way to cause worse congestion.

People also change from the slower moving lanes to adjacent faster moving lanes - thereby equalising the speed and congestion levels of all the lanes. This both improves safety (as large speed differentials between lanes is a significant hazard), and improves throughput by moving traffic from the most congested lanes to those lanes that are less congested. This effect is always either positive or zero. Unless there are a lot of morons trying to prevent it from happening.

People do not change lanes just for a change of scenery. And even if they did, trying to discourage them is a worse option than helping them to do so with the least possible disruption.

Allowing thirty cars to 'get in front of you' - and be honest, most of the situations I am describing would lead to fewer than ten cars taking advantage of the space you leave - could add as much as a whole minute to your journey time (but only if you are obeying the two second rule. More likely, you are being a dick, and only leaving a one second gap, so allowing in 30 adds half a minute to your arrival time). Is less than one minute worth the risk of a fender-bender?

In traffic with gaps, maybe 30 people slide in in front of you, costing you a minute; In traffic with no gaps, perhaps you succeed in discouraging half of them - the other half push in anyway, to avoid missing their exit, and cost you maybe 5-10 seconds each, because the lack of a gap means you have to come to a full halt. That's 75 - 150 seconds. And these are optimistic numbers for your hypothesis. Even if there was no increase in risk, keeping the gap small does nothing to help, and may do a lot to hinder, your overall progress.

 

[fromderinside]

By closing the gaps, drivers 'solve' the non-problems of other drivers making lane changes, and of empty sections of road being available; but are acting counter to the solution of the actual problem - that of improving the throughput of the road.

My view is that anything that leads to more maneuvering tends to ultimately overload drivers so that in a manageable congested freeway situation collapses to traffic jam. My presumptions are changes in stream produces changes in behavior altering flow. We study such in workload studies. Increasing information input and decisions ultimately overwhelms the individual. Lane changes as situations that increase operator workload. Not only are speeds changed, but, monitoring increases to adjacent lands from front back monitoring in same lane situations.

If you like that is just me.

Or you can take the results of this study which says essentially the same thing. Lane-changing in traffic streams http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.94.4905&rep=rep1&type=pdf

This study recommends

Since the spatial distribution of lane changes and the difference in lane speeds are found to be important determinants of bottleneck capacity, traffic managers may be able to increase capacity by forbidding lane changes and/or posting speed advisories at key locations upstream of bottlenecks; e.g. , as in Dagnanzo et al (2002)

Or drivers familiar with congested conditions decrease spacing between vehicles likely reducing land changes that exacerbate bottle neck formation. rat tat bumpf

If you really need more human factors, please keep up your physics view apology tour.

 

[bilby]

My view is that anything that leads to more maneuvering tends to ultimately overload drivers so that in a manageable congested freeway situation collapses to traffic jam.

And your view is wrong. To a man with a hammer, everything looks like a nail. But this isn't avionics; perhaps if you had spent more of your time at Boeing talking to Air Traffic Controllers, you would have a better grasp of the real drivers of traffic congestion. Congestion is not typically caused by drivers suffering cognitive overload; it is caused by there being a vehicle already occupying the space a driver would otherwise prefer to enter, thereby forcing him to brake or evade.

My presumptions are changes in stream produces changes in behavior altering flow.

A point on which we agree

We study such in workload studies. Increasing information input and decisions ultimately overwhelms the individual.

But that is NOT the situation in traffic. There are actually fewer demands on the driver as traffic becomes congested and slows down; and these demands are reduced still further if he leaves a large gap, into which another driver can merge without compromising the safety envelope. Because you can bet your boots that almost all drivers who want to merge WILL MERGE, whether there is space or not - and if there is not, the impact on traffic flow will be dramatic, even if there is no collision.

Lane changes as situations that increase operator workload. Not only are speeds changed, but, monitoring increases to adjacent lands from front back monitoring in same lane situations.

Real, but tiny. They don't make an important contribution, unless a driver is already so cogntively impaired that he should not be on the road.

If you like that is just me.

Or you can take the results of this study which says essentially the same thing. Lane-changing in traffic streams http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.94.4905&rep=rep1&type=pdf

This study recommends

Since the spatial distribution of lane changes and the difference in lane speeds are found to be important determinants of bottleneck capacity, traffic managers may be able to increase capacity by forbidding lane changes and/or posting speed advisories at key locations upstream of bottlenecks; e.g. , as in Dagnanzo et al (2002)

Or drivers familiar with congested conditions decrease spacing between vehicles likely reducing land changes that exacerbate bottle neck formation. rat tat bumpf

If you really need more human factors, please keep up your physics view apology tour.

That paper is describing the problem that is caused by traffic being too close together to begin with - if sufficient gaps were being left, a vehicle merging ahead would not disrupt the lane it enters.

It is an accurate description of how engineers can try to cope with the stupidity of people who have swallowed your half-baked theories on traffic flow; But there is nothing so useless as doing, with great efficiency, something that should not be done at all. If people didn't drive like fuckwits, the problem being discussed in that paper would not exist in the first place - and given that the solutions presented therein are outside the control of the individual motorist, there is NOTHING there to indicate what driver behaviours are appropriate or effective at minimising congestion and delay.

Unless your grand plan, if stuck in traffic, is to nip out and change the speed limit signs, and/or road markings?