Last week, Los Angeles became the first major city in American to coordinate all its traffic signals. The city spent $410 million coordinating signals at 4,000 intersections, or about $100,000 per intersection.
The $410 million cost is less than the cost of one mile of L.A.’s proposed Westside Subway Extension and about the same as the cost of two miles of Portland’s latest light-rail line. Yet the signal coordination will do far more to relieve congestion, save energy, and reduce air pollution than both of these rail projects put together–more, in all probability, than all rail transit projects in the United States.
A combination of behavioral and cognitive therapy, CBT focuses on the beliefs and thoughts that influence the parent’s own sense viagra generic sale of well-being. The most typical is alprostadil (prostaglandin) which is treated into levitra 20mg australia the member. For that viagra uk robertrobb.com reason it is recommended that you avoid drinking alcohol when taking this medicine. It is preferred by almost all the impotence affected people. acheter pfizer viagra robertrobb.com The city estimates that signal coordination will increase average travel speeds by 12 percent and reduce delays by 16 percent. L.A. Mayor Villaraigosa says the effort will save nearly a million metric tons of carbon, but he doesn’t say over what time period so presumably that is over the expected life of the project, not per year.
Villaraigosa has been mentioned as a possible replacement for outgoing Secretary of Immobility Ray LaHood. The mayor has championed the creation of a federal infrastructure bank to help cities like his make transportation improvements, but his support for the Westside Subway and other rail projects suggests he doesn’t really care about the cost-effectiveness of government spending. It is possible that this announcement was made in order to boost his chances for the secretary’s office. At least he isn’t openly campaigning for the position as former Minnesota Representative James Oberstar is doing.
Incidentally, many of the press reports and even many traffic engineers refer to this as “signal synchronization.” The Antiplanner dislikes this term as the signals aren’t being synchronized–if all signals turned red or green at the same instant, people would still have to frequently stop.
The term “synchronization” is a throw-back to when each signalized intersection was coordinated with a mechanical system that relied on a clock. For the coordination to work, the clocks in all of the mechanisms had to be kept synchronized. Modern, computer-driven systems work differently and so the term “synchronized” is obsolete. Of course, people use lots of other obsolete terms in everyday language, so I am probably fighting a losing battle.
410 million to remove a million tons of CO2. That’s still 4 times what O’Toole recommends in regards to CO2 sequestering. His publications regard various carbon sequestering schemes should cost no more than 50-100 dollars per ton while criticizing other programs particularly federally funded transportation systems whose costs come higher at a thousand to five thousand dollars per ton. “Cato estimates that the cost of reducing a ton of emissions through more fuel-efficient cars is near zero and the cost of reducing a ton by reducing traffic congestion through traffic signal coordination is less than 50-100 dollars. In contrast, the cost of reducing emissions through rail transit is close to $5,000 per ton.” Not the 50-100 reported but $410 is lower than thousands. Even with said improvements it’s not gonna do much for LA air quality issues; living between the Los Angeles Basin and the San Fernando Valley makes the city susceptible to atmospheric inversion (where the layers of cool dense air go down the valley and press against the warm contaminated air already in the valley), which holds in the exhausts from road vehicles, airplanes, factories, etc, the smog season lasts from May-October, since LA gets little rain that absorbs the pollutants, it’s a chronic problem but not as bad as it used to be. The Tennessee Valley area has the same problem.
The Antiplanner wrote:
Incidentally, many of the press reports and even many traffic engineers refer to this as “signal synchronization.” The Antiplanner dislikes this term as the signals aren’t being synchronized–if all signals turned red or green at the same instant, people would still have to frequently stop.
“Improved signal timing” might be a better phrase.
The city estimates that signal coordination will increase average travel speeds by 12 percent and reduce delays by 16 percent. L.A. Mayor Villaraigosa says the effort will save nearly a million metric tons of carbon, but he doesn’t say over what time period so presumably that is over the expected life of the project, not per year.
Re-timing signals should also improve safety for all users of the L.A. street network, including bicyclists and pedestrians.
I am all about saving time and money and reducing traffic congestion.
I don’t think we should allow carbon emissions to be part of the discussion. It is as yet unproven that a single human being has come to harm as a result of increasing CO2 concentration in the atmosphere. It is a fact that CO2 is a necessary element in the atmosphere. All life on earth depends on the presence of CO2 in the atmosphere. It is also a fact that CO2 levels have been as high as 2000 ppm in the last 100 million years – with a higher diversity of life on the planet during that epoch. Declining CO2 levels on earth correspond strongly with reduced species numbers and increased desertification. It is folly to take steps to reduce atmospheric CO2 levels without knowing fully the hazards of reduced CO2 levels.
C. P. Zilliacus: “L.A. Mayor Villaraigosa says the effort will save nearly a million metric tons of carbon, but he doesn’t say over what time period so presumably that is over the expected life of the project, not per year. ”
The mayor did not say precisley the timeframe it took to save a million tons. If after spending 410 million dollars, then paying into it for maintainence each year, factoring inflation and additional cars/trucks on the road circa 2025? It begs the question was this a wise investment, perhaps in terms of time saved or gas saved but could it have been done cheaper. Maybe other cities, but Los Angeles where they stack freeways on top of freeways.
“Last week, Los Angeles became the first major city in American to coordinate all its traffic signals. ”
Does that really work? Some junctions, due to platoon dispersal, aren’t going to co-ordinate very well. Those junctions should not have been included.
The article attached suggests that more than vanilla co-ordination was also done – some kind of actuation has been done.
There are also improvements to signal staging which can be done. These will also reduce delay and pollution. In some circumstances, removing the traffic signals (and just about everything else) can radically improve things. This video clearly shows the improvement possible.
http://www.youtube.com/watch?v=-vzDDMzq7d0&feature=youtu.be
” The Antiplanner dislikes this term as the signals aren’t being synchronized–if all signals turned red or green at the same instant, people would still have to frequently stop.”
Synchronisation implies that all cycles begin with a fixed reference to a zero time. So one cycle can run at 20s, 70s, 120s – another at 50s, 100s, 150s. As long as the cycle times are the same, the traffic signals are synchronised in perfect unison, with markedly reduced stop times.
Different topic, but worth sharing.
http://www.theatlanticcities.com/commute/2013/02/does-light-rail-encourage-people-stop-driving/4800/
With gas at $4/gallon and rising, this system will pay for itself in a very short time span. Nothing is more aggravating than to listen to government-types lecturing us on saving gas and then wasting huge amounts of gas by hitting 5 red lights in 5 blocks.
Hopefully, they did a good job and will monitor changes as traffic patterns change.
As an aside, New York City (of all places) does one thing right. The lights on the north-south avenues are coordinated and I have often gone 30-40 blocks without having to stop.
This is wonderful news. Yet in the meantime, as John 1000 mentioned, places like Portland and the Seattle area lecture us on carbon, then proceed to time lights so that drivers catch a maximum of red lights, causing huge delays, a waste of fuel, and wear & tear on vehicles. Hypocrisy much? Heck, criminal in my opinion.
Proper synchronizing of New York City’s streets shouldn’t be so difficult. They waffle ironed the city back in 1811 so nearly every street and avenue is perpendicular, still that’s a lot of intersections.
Even understanding the underlying chemistry of CO2 is challenging. Many of the plants we eat today evolved in an atmosphere where CO2 existed in much higher levels than what exist today. Logic would tell us that slightly higher CO2 levels would benefit plants considerably. For much of the last 100 million years levels existed as high as 1,000-2000 parts per million and some as high as 6,000. Levels are now at 380 parts per million which is a 140% increase over 280 ppm before humanity industrialized. However keep in mind; IF IT EVER GOT BELOW 140 ppm it becomes extraordinarily difficult for plants to want to photosynthesize; that’s the breaking point which came close to happening during prior Ice Ages. In 1987 an experiment performed by Dr. Sherwood Idso, orange trees were grown in enclosures, one of which was open to and contained a standard atmosphere given the amount of CO2 the time the experiment was run (300-330 ppm). The other enclosure had twice the amount of carbon pumped into the enclosure and escapes above (600 ppm). The growth of the orange trees and weight of the fruit harvested were closely monitored for years. There is no way to truly know how trees will respond to long-term atmospheric CO2 enrichment without actually doing a long-term experiment and the experiment runs even today. All and all, the enriched trees suffered no ill and produced 180% greater biomass than the tree’s grown in a normal atmosphere. We may need the benefit of CO2 enrichment in the future in order to feed future populations. The threat of climate is certainly the loudest of political arguments and for good reason because climate change is fueling hundreds of thousands of jobs be they the cryers or the deniers. From climatologists to lobbyists to industry analysts to carbon traders, economists and people selling fanciful ad hoc Earth saving snake oil. It’s easy to get funding when scenarios regarding doom and gloom. When asked backstage at London’s Live 8 concert in 2005, organized to raise awareness of the plight of starving Africans and ‘Make Poverty History’, Madonna embarrassingly admitted never setting foot on the continent. While Bono rips governments for their failure to address poverty and environmental issues, his polluting band’s finances had been moved to offshore accounts to avoid excessive taxation. No-one likes paying tax especially the rich, but few can afford it more so than them. Tax that will go some way to financing causes far more worthwhile than Bono’s. The whole thing outta be, if you don’t practice what you preach, you probably shouldn’t be telling others how to live.
And for those pulling out the shovel’s; tree’s will do relatively little to help with CO2 emissions. Even if you replanted all of North America you’d sequester only a portion of the US’ emissions. But not enough to handle Canada, China, India, Europe, Sub-Saharan Africa and Australia. It’s the soil, which has 3-4 times more carbon than the vegetation above them. If disturbed by planting activities they’ll release carbon with a vengeance. And trees have a habit of dying and decomposing, which puts a lot of that CO2 back into the atmosphere so decades of planting can easily be undermined. And since our goal is to pull CO2 permanently, trees are not the best solution. Most of the planets oxygen was/is produced from bacteria, algae, diatoms, and plankton that live in the sea. They absorb more carbon in a day than the Amazon does in a month. When they sequester carbon they also sequester minerals to build “skeletons”. Assuming they aren’t eaten (which most of them are providing most of the worlds biomass) they die naturally and sink to the bottom of the sea in a phenomenon known as “marine snow” to be buried under sediment for hundreds of thousands of years hopefully before they are eaten by bottom dwelling marine life which release carbon yet again. Being locked in mineral form buried on the sea floor is how much of the globes carbon has been handled throughout geologic history. It’s not to say tree’s aren’t useful. They can shade or windbreak a house reducing heating/AC use 10-15% so indirectly they lower emissions. They provide habitat, food for both wildlife or humans, situate micro-climate, humidify the atmosphere, lock in soil moisture, absorb pollution and volatile organics, provide shade, prevent soil erosion, restore river habitat and all and all they’re aesthetically attractive that’s enough reason to plant them.
Some of the anti-car folks like congestion, thinking the worse congestion is, the more likely people will shift to other modes. They support so-called traffic calming measures and oppose increasing road capacity, believing that these things will reduce car usage. But even if they did, any resulting reduction in emissions would likely be offset by increased emissions from the remaining vehicles. They don’t recognize (or at least acknowledge) that emissions increase greatly when a vehicle travels at less than 25-30 mph, up to several fold at the slowest speeds. Fuel usage and emissions are minimized at speeds between 25-30 and 55-60 mph. So if you’re really concerned about reducing emissions, you ought to support actions that will keep traffic moving at a steady speed and minimize slowing and stopping of vehicles. Reducing bottlenecks does this, traffic calming measures do just the opposite. It seems that they’ve lost sight of the real goal of minimizing the car’s negative impacts, and reducing car usage has become the goal in and of itself. They are not the same thing.
Ahh Yes …. The myth of synchronized traffic lights matched to the speed of vehicular traffic resulting in more efficiency.
In certain very specific circumstances, it’s even possible to make this seem to actually happen as mentioned earlier with the New York City example. But dig a little deeper into the problem and it quickly becomes clear why this is pretty much impossible to actually accomplish for any significant period of time. Imagine for a moment a trough of water. What we want to accomplish is to send “Waves of traffic” down this corridor with the peaks of the waves representing the Green Lights and the troughs being the red lights. We start at one end and send out our wave . If we travel down the trough in time with the waves it’s easy to always be “surfing the crest”. No Problem. But traffic on a street flows both directions. Look at the “waves” from the opposite end. If we travel in the opposite direction as the waves , at the same speed as we did before, the timing is all wrong. If the spacing of the intersections is constant , then may there is a speed where it is possible to cross each intersection on a “wave Peak” but that speed is an function of the distance between intersections and not the same as the speed in the opposing direction. Now remember, that we also need to deal with the timing of the lights at the intersections with the streets at a 90 angle. Maybe we can find a harmonic speed where waves traveling north and waves traveling east are “in Sync” ( ie the east bound peaks match up with the north bound troughs ) but that speed also more now makes travel in the opposing directions 4 times slower. And that’s in an Ideal ( non existent) world. Out in the real world blocks are not square. There are streets that come in at angles. Vehicles moves at different speeds and in different volumes. Pedestrian walk requests impact light cycles. Plus there are many more variables that impact the needed algorithm.
Just like a government “Budget Savings” there is no such thing as “Synchronized traffic lights”.
It is certainly true that there is no such thing as a perfectly synchronized traffic signal system. However, one can improve how well a system is synchronized. Improving the degree to which a signal system is synchronized can result in a real improvement in the average delay times and speeds for travelers. Like with many other things, perfection will never be achieved. However, this does not mean things can not be improved a lot.
Doesn’t coordinating signal lights fall in the category of “great ideas from the 1970s”?
No….. The math flat does not work. Any gain you might achieve is at the expense of the traffic in the opposeing direction. Even if you attempt to sync to inbound in the AM and Outbound in the PM that assumes the traffic is all flowing in prdictable directions and at a predictable speed and in predictable volumes, which it is not. There are just too many varibles to make significant improvements. You may be able to maximize the flows in serveral key intersections but all you’re really doing is speading the wait times out over a broader area to different choke points.
Dilbert – The synchonization works dramatically well on one-way streets, as in many downtown districts, where main thoroughfares were split into separate one-way streets.
“No….. The math flat does not work.”
This is incorrect. The maths works just fine. The calculations are done by computer, as they can be long-winded. A piece of software like SYNCHRO or VISTRO or TRANSYT can do the calculations easily, finding the optimum combination of cycle times and offsets.
If you want to see this in action, demo versions of the software are available for free.