Traffic

Traffic congestion

Traffic congestion is a condition on networks that occurs as use increases, and is characterized by slower speeds, longer trip times, and increased queuing. The most common example is the physical use of roads by vehicles. When traffic demand is great enough that the interaction between vehicles slows the speed of the traffic stream, congestion is incurred. As demand approaches the capacity of a road (or of the intersections along the road), extreme traffic congestion sets in. When vehicles are fully stopped for periods of time, this is colloquially known as a traffic jam.

Causes

Traffic congestion occurs when a volume of traffic or modal split generates demand for space greater than the available road capacity, this is point is commonly termed saturation. There are a number of specific circumstances which cause or aggravate congestion; most of them reduce the capacity of a road at a given point or over a certain length, or increase the number of vehicles required for a given volume of people or goods. About half of U.S. traffic congestion is recurring, and is attributed to sheer weight of traffic; most of the rest is attributed to traffic incidents, road works and weather events. Speed and flow can also affect network capacity though the relationship is complex

Traffic research still cannot fully predict under which conditions a "traffic jam" (as opposed to heavy, but smoothly flowing traffic) may suddenly occur. It has been found that individual incidents (such as accidents or even a single car braking heavily in a previously smooth flow) may cause ripple effects (a cascading failure) which then spread out and create a sustained traffic jam when, otherwise, normal flow might have continued for some time longer

Mathematical theories

Some traffic engineers have attempted to apply the rules of fluid dynamics to traffic flow, likening it to the flow of a fluid in a pipe. Congestion simulations and real-time observations have shown that in heavy but free flowing traffic, jams can arise spontaneously, triggered by minor events ("butterfly effects"), such as an abrupt steering maneuver by a single motorist. Traffic scientists liken such a situation to the sudden freezing of super cooled fluid. However, unlike a fluid, traffic flow is often affected by signals or other events at junctions that periodically affect the smooth flow of traffic.

Because of the poor correlation of theoretical models to actual observed traffic flows, transportation planners and highway engineers attempt to forecast traffic flow using empirical models. Their working traffic models typically use a combination of macro-, micro- and macroscopic features, and may add matrix entropy effects, by "platoon" groups of vehicles and by randomizing the flow patterns within individual segments of the network. These models are then typically calibrated by measuring actual traffic flows on the links in the network, and the baseline flows are adjusted accordingly.

It is now claimed that equations can predict these in detail:

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

Economic theories

Congested roads can be seen as an example of the tragedy of the commons. Because roads in most places are free at the point of usage, there is little financial incentive for drivers not to over-use them, up to the point where traffic collapses into a jam, when demand becomes limited by opportunity cost. Privatization of highways and road pricing have both been proposed as measures that may reduce congestion through economic incentives and disincentives. Congestion can also happen due to non-recurring highway incidents, such as a crash or roadwork’s, which may reduce the road's capacity below normal levels.

Economist Anthony Downs, in his books Stuck in Traffic (1992) and Still Stuck in Traffic (2004), argues that rush hour traffic congestion is inevitable because of the benefits of having a relatively standard work day. In a capitalist economy, goods can be allocated either by pricing (ability to pay) or by queuing (first-come first-serve); congestion is an example of the latter. Instead of the traditional solution of making the "pipe" large enough to accommodate the total demand for peak-hour vehicle travel (a supply-side solution), either by widening roadways or increasing "flow pressure" via automated highway systems, Downs advocates greater use of road pricing to reduce congestion (a demand-side solution, effectively rationing demand), in turn plowing the revenues generated there from into public transportation projects. Road pricing itself is controversial; more information is available in the dedicated article.

Traffic problem in Bangladesh

Dhaka, the capital city of Bangladesh, has a great variety of tradition. Dhaka's eye-catching architectures and other famous installations are known and acclaimed at home and aboard. This is the city with historical background and loved by visitors at home and abroad for Shaheed Minar, National Museum, Lalbagh Kella, Dhaka University, Ramna Park, Suhrawardy Udyan, Mirpur Zoo and many other beautiful and historical places of interest. Being the capital city, Dhaka has many advantages for higher and specialised education, employments, trade and commerce. As such, Dhaka always attracts people from other parts of the country. Apart from many advantages, Dhaka is burdened with many problems also, namely - housing problem, sanitation problem and problem related to water logging, etc. Yet, among many other problems, Dhaka city has been experiencing severe traffic-problem which is a common phenomenon in the city.

The city-dwellers, city-planners, policy makers, the experts and researchers who think about the city will unanimously agree that Dhaka is one of the most unplanned cities of the world. It is certainly a wonder how this megapolis manages to survive. Nonetheless, it manages to function somehow.

The inhabitants living in this city are now approximately over 10 million, although there is perhaps no statistics about the exact number of population of Dhaka city. Survey carried out randomly by different authorities provided different data about the number of population in the city. However, it is estimated that population of Dhaka will not be less than 15 million and yet the city is experiencing influx of population every day from different parts of the country due to the opportunities available and lack of opportunities in the areas from where they come.

Dhaka city is lengthy in south and northern directions while its width consisting of east and western directions is few kilometers only. There is hardly any scope of its expansion in eastern and western side to a visible extent.

Dhaka city situation is more alarming mainly due to vehicular movement and traffic jam. There are different types of vehicular namely, car, bus, jeep, truck, minibus, microbus, auto-rickshaw, tempo, mini-truck, motorcycles and innumerable numbers of rickshaws. Many of the vehicles that ply on Dhaka's streets daily are faulty and emit black smoke in excess of the prescribed limit. Black smoke is primary unburning carbon that is agglomerated into small particles caused by over-load and faulty engine condition of vehicles.

Among others, notable causes of traffic jam include violation of traffic rules, deplorable road condition, random stoppage of vehicles, unauthorised parking and use of footpath illegally. Moreover, for growing urbanisation and affluence, the number of vehicles is also rising, contributing to more and more traffic jams. Narrow roads and congestion are aggravating the situation further. To quote AKM Shahidul Haque, Dhaka Metropolitan Police Commissioner that one of the main reasons of traffic-jam is due to unauthorised parking of vehicles here and there.

It is learnt that registered number of rickshaws available in Dhaka city is around 86,000 but actual number of the rickshaws is likely to be many times more having no registration. This poses serious threat in the traffic system of Dhaka city.

There are three bus terminals in the city. These are: Mohakhali, Gabtoli and Sayedabad. There is a bus stand at Phulbaria, Gulistan. There are innumerable numbers of ticket counters adjacent to main traffic points. The worst traffic-vulnerable points include, among others, Jatrabari, Hatkhola, Shapla Chattar, Gulistan, Dainik Bangla, Paltan, New Market, Science Laboratory area, Shahbag, Bangla Motor, Sonargaon-crossing, Panthopath, Farmgate, Manik Mian Avenue, Asadgate, Shyamoli, Kalyanpur, Gabtoli, Mirpur-Goolchakkar, Mohakhali, Khilgaon, Banani, Mouchak, Kakrail and Malibagh. Now-a-days residential areas are also experiencing heavy traffic-jam. The areas include Dhanmondi, Banani, Gulshan and other prime residential locations. This is due to establishment of many schools, colleges, private universities and other educational institutions in those areas. Moreover, many offices, particularly private-owned offices and factories, are also located in the residential areas resulting in heavy traffic-jam. Anybody crossing the areas can easily visualise the situation is grave as students with their guardians are waiting and waiting to reach destinations and others going to their work places.

Everyday work-hours are unnecessarily wasted due to traffic jam. It has a great economic impact on production and thus on our economy. Traffic-jam causes untold sufferings to the people going to offices and various destinations.

Traffic-jam causes air pollution which affects the respiratory tract, causes irritation, headache, fatigue, asthma, high blood pressure, heart diseases and cancer. Experts say if this trend continues unabated, most residents of the metropolis would become exposed to the risk of those ailments and different other health hazards and complications. The development of mental faculty of children would be impaired by lead pollution that could also affect the central nervous system and causes of renal damage and hypertension. The massive traffic congestion is taking its toll on human health, economy, environment and other anthropomorphic activities. This price tag is rather high when people have to spend hours unnecessarily on the road in sweltering heat, not to speak of the high humidity. The resulting misery generated by high heat and humidity takes its toll in human health. To add insult to the injury, the unpleasantness this high misery index generates slows down the productivity of a person.

The traffic problem of Dhaka is hindering the growth of this city and, at large, Bangladesh both. On every intersection the drivers become quite unruly. A first time visitor may think that people here are the most wild who have no respect for law of the land. This is indeed a serious matter. Behavioral scientists have long since done experiments to show that even insects demonstrate aggressive behaviour when they are placed in a crowded situation. Therefore, it comes as no surprise to see that Dhaka's pedestrians, the rickshapullers, babytaxi drivers, vanwallahs, and bus and truck drivers all vie for tiny spaces with noticeable aggression and utter disregard for others' right of way. This obviously creates serious problems such as unnecessary traffic holdup and some unhappy incidents. Serious vehicular-related accidents are growing at an accelerated rate for growing traffic problem.

By any calculation, if we note, Dhaka is not a city of vast areas. The width (east-west direction) is few kilometres. The city could have moved only in the North-South direction. This imposes a serious restriction on the availability of land. But this severe paucity of land had hardly diminished the growth rate of this city. Any legitimate city planner worth his merits would not recommend the city of Dhaka for people over 1-2 million. The ever-growing population had easily exceeded this capacity by 10 to 15 times already. And there is no sign that the population growth in this city is abating. The present road system of Dhaka, which is hardly adequate for moving vehicles for 1-2 million people, will virtually collapse when the population of this megapolis will increase further. It is hoped that urban planners of Dhaka are doing their clearheaded thinking right now or else the system will collapse right before their eyes.

Under the above perspective remedies are recommended as follows:

1. Policy makers, city planners, researchers and the related directorates and offices must sit together and find ways and means to address the problem. Coordination is very urgent and important.

2. Readjustment of office timings depending upon the nature of job of the offices.

3. No shop or other installation be allowed in the footpaths and nearby.

4. Every year Traffic Week is observed by the concerned department. More and more awareness be created to achieve the goal.

5. Shifting of educational institutes namely, private universities, school and colleges and other offices from residential zone to outskirts of the city.

6. More and more fly-overs and over-bridges be constructed to address the problem.

7. It is learnt that a mega plan is under consideration for underground rail. The plan be speeded up. The World Bank, IMF and ADB or other donor agencies may be approached in a planned way to materialise the plan.

8. Restriction on import of old and unnecessary vehicles be imposed rigidly.

9. There may be three blocks from Tongi Bridge to Jatrabati which will be treated as east block, middle block and west block. Road planning should be made accordingly for easy traffic movement.

10. Traffic management should be improved further for which necessary training or facilities may be available ..

11. Unregistered rickshaws must be withdrawn arranging alternatives for their employment.

12. Unauthorised parking of vehicles be stopped.

Traffic-jam takes serious turn during the holy month of Ramadan. In this view, concerned authorities are requested to look into the matter for a better situation for the benefit of the people. For easy and uninterrupted movement, Dhaka city without traffic jam is very much desireable. This will mitigate the sufferings of the people. Moreover, valuable time will also be saved. Violation of traffic rules be stopped. We do not want old and dilapidated vehicles in the streets. Nor we want unauthorised parking of vehicles here and there. We want a clean city free from traffic jam. It is encouraging that the government is working in this direction. Working together, we can achieve the goal.

It is reported that Government has decided to withdraw about 70,000 (seventy thousand) old and dilapidated vehicles from the road. Very old and decrepit vehicles will not be allowed to ply. All these measures are aimed at mitigating the problem.

Dreaming of a clean city free from traffic jam

YES, we are dreaming of a clean city free from traffic jam. This is about Dhaka, the capital city of Bangladesh. We dream of a city where at least there should have the basic amenities worth-living. But the city-dwellers living in Dhaka will unanimously say that these are lacking here. The city is now burdened with many problems namely - housing problem, sanitation problem, problem-related to water-logging etc. Yet, among many other problems, Dhaka city has been experiencing severe traffic jam which is a burning issue now-a-days.

The inhabitants living in this city are now approximately over 13 million, although there is perhaps no statistics about the exact number of population of Dhaka city. Survey carried out randomly by different authorities provided different data about the number of population living in the city. However, it is estimated that population of Dhaka will not be less than 15 million and yet the city is experiencing an influx of population everyday from different parts of the country due to the opportunities available here and lack of opportunities in the departing areas.

There are different types of vehicles namely car, bus, jeep, truck, minibus, microbus, auto-rickshaw, tempo, mini-truck, motor cycles and innumerable numbers of rickshaws. Many of the vehicles that ply on Dhaka's streets daily are faulty and emit black smoke in excess of the prescribed limit. Black smoke is primary unburning carbon that is agglomerated into small particles caused by over-load and faulty engine condition of the vehicles.

Among others, notable causes of traffic jam include violation of traffic rules, deplorable road condition, random stoppage of vehicles, unauthorised parking and use of footpath illegally. Moreover, for growing urbanisation and affluence, the number of vehicles is also rising, contributing more and more traffic jam. Narrow roads and congestion are aggravating the situation further.

There are three bus terminals in the city. These are: Mohakhali, Gabtoli and Sayeedabad. There is a bus stand at Phulbaria, Gulistan. There are innumerable numbers of ticket counters adjacent to main traffic points. The worst traffic-vulnerable points include among others: Jatrabari, Hatkhola, Shapla Chattar, Gulistan turn, Dainik Bangla, Paltan, Newmarket, Science Laboratory area, Shahbag, Bangla Motor, Sonargaon-crossing, Panthopath, Farmgate, Manik Mian Avenue, Asadgate, Shyamoli, Kallayanpur, Gabtoli, Mirpur-Goolchakkar, Mohakhali, Khilgaon, Banani, Mouchak, Kakrail and Malibagh etc.

Now-a-days residential areas are also experiencing heavy traffic jams. The areas include Dhanmondi, Banani, Gulshan and other prime residential locations. This is due to establishment of many schools, colleges, private universities and other educational institutions in those areas. Moreover, many offices, particularly private-owned ones and factories are also located in the residential areas resulting in heavy traffic jam. Anybody crossing the areas can easily visualise how the situation is grave as students with their guardians are waiting and waiting to reach destinations and others going to their work places. Everyday work-hours are unnecessarily wasted due to traffic jam. It has a great economic impact on production and, thus, on our economy. Traffic jam causes untold sufferings to the people going to offices and various other destinations.

Traffic jam causes air pollution. This affects the respiratory tract, causes irritation, headache, fatigue, asthma, high blood pressure, heart diseases and cancer. Experts say if this trend continues unabated, most residents of the metropolis would become exposed to the risk of those ailments and different other health hazards and complications. The development of mental faculty of children would be impaired by lead pollution that could also affect the central nervous system and cause renal damage and hypertension. The massive traffic congestion is taking its toll on human health, economy, environment and other anthropomorphic activities. This price tag is rather high when people have to spend hours unnecessarily on the road in sweltering heat, not to speak of the high humidity. The resulting misery generated by high heat and humidity takes its toll in human health. To add insult to the injury, the unpleasant aspects that this high misery index generates slow down the productivity of a person.

We may dream of a clean city free from traffic jam. This is possible if the policy makers, city planners, researchers and the related directorates and offices sit together and find ways and means to address the problem. Coordination is very urgent and important. Office timings may be re-adjusted, depending upon the nature of job of the offices. No shop or other installation should be allowed on the footpaths and nearby. Every year TRAFFIC WEEK is observed by the concerned department. More and more awareness has be created to achieve the goal. Shifting of educational institutions, namely private universities, schools and colleges and other offices from residential zones to the outskirts of the city can partly help address the problem. More and more fly-overs and over-bridges can be constructed to address it.

It is learnt that a mega plan is under consideration for underground rail. The plan can be speeded up. The World Bank, IMF and ADB or other donor agencies may be approached in a coordinated way to materialise the plan. Restriction on import of old and unnecessary vehicles can be imposed rigidly. There may be three blocks from Tongi Bridge to Jatrabati which will be treated as east block, middle block and west block.

Road planning should accordingly be made for easy traffic movement. Traffic management should be improved further for which necessary training or facilities may be available. Unregistered rickshaws can be withdrawn, arranging alternatives for employment of the rickshaw-pullers. Unauthorised parking of vehicles should be stopped.

If we all work in a coordinated way with sincerely and honestly -- and last but not the least with patriotism -- success towards a clean Dhaka city free from traffic jam should not be far away.

Negative impacts

Traffic congestion has a number of negative effects:

• Wasting time of motorists and passengers ("opportunity cost"). As a non-productive activity for most people, congestion reduces regional economic health.
• Delays, which may result in late arrival for employment, meetings, and education, resulting in lost business, disciplinary action or other personal losses.
• Inability to forecast travel time accurately, leading to drivers allocating more time to travel "just in case", and less time on productive activities.
• Wasted fuel increasing air pollution and carbon dioxide emissions (which may contribute to global warming) owing to increased idling, acceleration and braking. Increased fuel use may also in theory cause a rise in fuel costs.
• Wear and tear on vehicles as a result of idling in traffic and frequent acceleration and braking, leading to more frequent repairs and replacements.
• Stressed and frustrated motorists, encouraging road rage and reduced health of motorists
• Emergencies: blocked traffic may interfere with the passage of emergency vehicles traveling to their destinations where they are urgently needed.
• Spillover effect from congested main arteries to secondary roads and side streets as alternative routes are attempted ('rat running'), which may affect neighborhood amenity and real estate prices.
• Pollution caused by slow moving traffic. This is exacerbated if heavy diesel vehicles are part of the traffic flow.