Category Archives: Traffic System
Software KAJI (Kapasitas Jalan Indonesia) 1997 adalah piranti lunak yang digunakan untuk menerapkan metoda perhitungan yang dikembangkan MKJI (Manual Kapasitas Jalan Indonesia) 1997 yang bertujuan menganalisis kapasitas dan kinerja fasilitas lalulintas jalan (misalnya ruas jalan, simpang bersinyal, simpang tak bersinyal, dll).
Karena banyaknya permintaan mengenai software Kaji 1997, maka berikut ini saya unggah software Kaji 1997, agar dapat dipergunakan oleh seluruh mahasiswa yang sedang Tugas Akhir atau mengikuti mata kuliah Manajemen Lalu Lintas atau Rekayasa Lalu Lintas.
Software dapat didownload di sini.
Berikut ini adalah prosedur-prosedur perhitungan dan cara analisis perilaku lalulintas di simpang bersinyal dengan menggunakan software KAJI 1997.
Download di sini.
Countless hours are lost in traffic jams every year. Most frustrating of all are those jams with no apparent cause — no accident, no stalled vehicle, no lanes closed for construction.
Such phantom jams can form when there is a heavy volume of cars on the road. In that high density of traffic, small disturbances (a driver hitting the brake too hard, or getting too close to another car) can quickly become amplified into a full-blown, self-sustaining traffic jam.
A team of MIT mathematicians has developed a model that describes how and under what conditions such jams form, which could help road designers minimize the odds of their formation. The researchers reported their findings May 26 in the online edition of Physical Review E.
Key to the new study is the realization that the mathematics of such jams, which the researchers call “jamitons,” are strikingly similar to the equations that describe detonation waves produced by explosions, says Aslan Kasimov, lecturer in MIT’s Department of Mathematics. That discovery enabled the team to solve traffic jam equations that were first theorized in the 1950s.
The equations, similar to those used to describe fluid mechanics, model traffic jams as a self-sustaining wave. Variables such as traffic speed and traffic density are used to calculate the conditions under which a jamiton will form and how fast it will spread.
Once such a jam is formed, it’s almost impossible to break up — drivers just have to wait it out, says Morris Flynn, lead author of the paper. However, the model could help engineers design roads with enough capacity to keep traffic density low enough to minimize the occurrence of such jams, says Flynn, a former MIT math instructor now at the University of Alberta.
The model can also help determine safe speed limits and identify stretches of road where high densities of traffic — hot spots for accidents — are likely to form.
Flynn and Kasimov worked with MIT math instructors Jean-Christophe Nave and Benjamin Seibold and professor of applied mathematics Rodolfo Rosales on this study.
The team tackled the problem last year after a group of Japanese researchers experimentally demonstrated the formation of jamitons on a circular roadway. Drivers were told to travel 30 kilometers per hour and maintain a constant distance from other cars. Very quickly, disturbances appeared and a phantom jam formed. The denser the traffic, the faster the jams formed.
“We wanted to describe this using a mathematical model similar to that of fluid flow,” said Kasimov, whose main research focus is detonation waves. He and his co-authors found that, like detonation waves, jamitons have a “sonic point,” which separates the traffic flow into upstream and downstream components. Much like the event horizon of a black hole, the sonic point precludes communication between these distinct components so that, for example, information about free-flowing conditions just beyond the front of the jam can’t reach drivers behind the sonic point. As a result, drivers stuck in dense traffic may have no idea that the jam has no external cause, such as an accident or other bottleneck. Correspondingly, they don’t appreciate that traffic conditions are soon to improve and drive accordingly.
“You’re stuck in traffic until all of the sudden it just clears,” says Morris.
In future studies, the team plans to look more detailed aspects of jamiton formation, including how the number of lanes affects the phantom traffic jams.
The research was funded by the U.S. Air Force Office of Scientific Research, the National Science Foundation and the (Canadian) Natural Science and Engineering Research Council.
M. R. Flynn, A. R. Kasimov, J.-C. Nave, R. R. Rosales, and B. Seibold. Self-sustained nonlinear waves in traffic flow. Physical Review E, 2009; 79 (5): 056113 DOI
(source : sciencedaily)
The Research Group in Mathematical Programming, Logistics and Simulation (PROMALS) and the Seat Chair of Innovation and Sustainable Development (Seat-UPC) create technological solutions to improve traffic flow, make driving safer and more comfortable, lower the accident rate and reduce traffic congestion and emissions of contaminant gases.
New advances will see vehicles equipped with sensors and interfaces which gather information on the traffic situation and display it on screen or alert the driver through automated voice announcements. The Seat-UPC Chair is involved in designing and fitting human machine interfaces (HMIs) and running automated tests of the electronic systems used in the MARTA project, which incorporate new technologies such as specialized image recognition applications.
New on-board sensors will be able to monitor the status of mechanical components such as brakes when a vehicle is in motion, while others will provide automatic control of driving speed and the distance maintained from the vehicle in front. Interfaces will enable data to be shared between vehicles, providing updated information on their position and speed every 200 meters. A system of nodes installed in the road network transmits the data to a mobility management center, where they are processed and used to maintain traffic flow by providing real-time information on congestion spots and suggesting optimum routes in the event of an accident.
The PROMALS group, attached to the Department of Statistics and Operations Research at the UPC, is looking at ways of using the data received by the management center. Its researchers are designing simulated traffic scenarios in which to test the new technologies developed under the MARTA project: a recent example is a traffic priority system in which the real-time data are used to determine the ideal intervals between traffic light phases across a given area, which optimizes traffic flow and reduces congestion.
The MARTA project has a budget of over thirty-five million euros and receives funding from the Center for the Development of Industrial Technology (CDTI). The project, scheduled for completion in 2011, is coordinated by the company FICOSA as part of a wider program run by the National Strategic Consortium in Technical Research (CENIT), and brings together experts and researchers from nineteen companies and nineteen scientific centers and national universities.
Source : sciencedaily
Environmental activists on Monday urged the Jakarta Administration to temporarily halt its car-free days on selected city roads, saying a re-evaluation was needed because the event had failed to reduce air pollution and loose regulations have resulted in many violations, including those by senior officials.
“Legally, the car-free days cannot be stopped, but the city administration should halt them temporarily and conduct a review of what went wrong. Honestly, it’s been such a waste,” Selamet Daroyni, the executive director of the Jakarta branch of Indonesian Forum for the Environment, or Walhi, told a press conference.
Selamet said car-free days, generally on Sundays, had failed to achieve the short-term objective of minimizing air pollution and also had failed to encourage Jakarta residents to be more environmentally friendly and less dependent on cars.
“If we perceive this issue from the three success indicators, I’d say these events did not help much,” Selamet said.
He said the indicators were public participation, air pollution reduction and public obedience, including by government officials and law enforcers.
Ahmad Safrudin, of the Committee for Phasing Out Leaded Gasoline, said car-free days merely relocated traffic flow from one place to another without reducing air pollutants.
He said that a report by the Jakarta Environmental Management Board, or BPLHD, that air pollution has decreased significantly was unreliable.
“Jakarta has five air quality monitoring systems, but only one of them is working, so I doubt the report,” he said.
Ahmad said the inefficiency of car-free days had been proven by many violations, with some of the violators being government officials and policemen.
Responding to criticism, Rina Suryani, the BPLHD head of natural resources monitoring, said they had scientific measurements to prove that car-free days had in fact contributed significantly to air pollution reduction.
“In some parts of Jakarta, the air quality has gotten better because of this program,” she said.
Rina said the board could not enforce sanctions against violators because the 2005 bylaw enabling car-free days had not stipulated any.
Jakarta’s car-free days began in September 2007 and are held on the last Sunday of each month.
This year BPLHD has scheduled 22 road closure events.
Source : http://www.thejakartaglobe.com
Photo : http://bataviase.files.wordpress.com
February 23, 2009, by Dessy Sagita
So what are the true costs of congestion? It seems as if nobody really knows. At a recent Transport Select Committee evidence session into road user charging, MPs seemed less than satisfied with the answers they received. The CBI has estimated that congestion costs the economy approximately £20 billion. With 40% of congestion in London, this fits with TfL’s figure of £7-8 billion. However, the Committee appeared extremely sceptical about the exact quantification of the monetary value of congestion.
Moreover, the results of proposed charging schemes will not always produce the desired resuts. It has become clear that in the last three years any reduction in congestion as a result of the central London charging zone has effectively been eradicated by the reduction in road capacity, owing to road works and essential maintenance carried out by the utility companies. This has meant that levels of congestion have slowly crept back towards pre-2003 levels despite the fact that there is approximately 20 per cent less traffic entering the central London zone. Hence, Kulveer Ranger, Director of Transport at TfL, has called for a coordinated implementation of transport policies that complement the existence of the congestion zone.
Whilst the Department for Transport has not itself made an official measure of the costs of congestion, it has questioned the £20 billion estimate and suggests that a national road pricing scheme could achieve ‘time’ savings of £10 billion a year. It appears that no consistent methodology has been applied, whilst there have been criticisms of the value which the DfT places upon time. Hauliers are not alone in believing that ‘time’ should mean the period it takes to get a product onto the shop shelf.
Road user groups often make the argument that motorists pay more in transport-related taxes than the Government invests in transport services. However, road transport imposes many different costs on society, some of which are borne by the road user, but others are borne by society at large. Consequently, there will always be calls for the ‘polluter pays’ principle, yet such a policy would be problematic politically. Whilst it is necessary to recognise that taxes raised from one sector of industry may be passed on to vital areas such as health and education, it is essential that such a process is transparent so that taxpayers can see where their money has been invested. Although the public may support investment in the public transport network they are unlikely to accept any new, additional tax on motoring – congestion charging or otherwise – until such investments are delivered. This is a lesson from Manchester.
Some of the costs of congestion such as inefficiency, missed appointments, late arrivals, and overrun schedules are borne by employers. Yet it is employees who bear the costs of commuting, accounting for a quarter of the costs of motoring, which the Telecommuting 2000 research project estimates to be £13.5 billion in total per year. According to the project, each year employers lose at least £20 billion through congestion, and employees pay £13.5 billion to commute by car, making a much higher estimate than the CBI’s, of £33.5 billion per year. It is worthy of note that such estimates do not even consider the effects on the environment, on employees’ health or the “work/life balance”. It is also unclear what price of a barrel of oil has been used in these estimates. Consequenlty, the true costs of congestion may be much higher than anyone has even dared to ‘guestimate’.
Source : http://www.transportinfo.org.uk
Photo : http://images.drive.com.au