Road Congestion / Traffic Congestion
Road Congestion is a condition that is characterized by longer trip times, slow traffic flow, and increased queeing. Traffic jam is a colloquial term for a period of extreme traffic congestion. Road Congestion happens when: 1. there is high traffic volume 2. construction 3. accidents/disasters 4. bad wheather condition. There are several negative effects of Traffic Congestion. One negative effect is it wastes both the time of the motorists and passengers. It also causes tardiness. Many people especially those who need to arrive promtly for work, school or business meetings. Increased idling, acceleration, and braking cause fuel loss and air pollution. It also causes stress to the motorists and passengers alike.
Traffic congestion is a classic externality, especially pervasive in urban areas. The theoretical and empirical relationships governing it have been thoroughly studied. As a result, most urban economists and a growing number of other policy analysts agree that the best policy to deal with it would be some form of Congestion Pricing. Such a policy involves charging a substantial fee for operating a motor vehicle at times and places where there is insufficient road capacity to easily accommodate demand. The intention is to alter people’s travel behavior enough to reduce congestion. Three cities have seriously considered congestion pricing of a city center, each pioneering a different method of applying or implementing the concept. Singapore was the first to design and implement a practical, low-tech scheme for congestion pricing. Singapore’s initial system was very simple: the priced area is defined by a single cordon line surrounding the city center, the technology consists of paper windshield stickers, and enforcement is through visual inspection by traffic officers. Hong Kong was the pioneer in fully automated charging; its electronic road pricing (ERP) scheme was a flexible and comprehensive system involving multiple cordons. For Cambridge, England, the new concept was congestion-specific charging, an attempt to more closely approximate the theoretical ideal of congestion pricing by making the charge vary in real time in a manner reflecting the severity of congestion actually encountered while inside the priced area. Only one of these systems is operational. Singapore’s Area License Scheme (ALS) was inaugurated in 1975 and still operates today; the city has recently inaugurated an electronic system to replace its manual charging and enforcement. Hong Kong’s ERP scheme was subjected to extensive technological field trials as well as exhaustive desk studies for prediction and evaluation, but was withdrawn due to public opposition. Cambridge has also been the site of a technological field trial but the scheme was abandoned when a new and unsupportive council came to power in 1993. Singapore’s ALS is part of an extremely stringent set of policies designed to restrict automobile ownership and use in this crowded island city-state of three million people. The national government chose the ALS over conventional road tolls and higher parking charges because space for toll stations was lacking in the city center and it thought higher parking charges would be ineffective in the face of heavy through traffic and numerous chauffeurdriven cars. The size and structure of the fee has varied over the years. When first implemented in 1975, the fee was imposed only on vehicles entering the restricted area during the morning peak period. There have been both intellectual and practical developments since Pigou first, put forward the idea of road pricing. The basic concept is deceptively easy; apply the price mechanism in the same way as it applies elsewhere. When there is high demand prices should be high to deter excessive use. Intellectually, the key question is one of defining the appropriate price in what is often a complex set of economic and technical circumstances. The key issue from a practical point of view is one of operationalizing the concept, not only in terms of developing technically efficient charging mechanisms but also in gaining political acceptance as a valid policy instrument.
Another innovation is the use of Inteligent Transportation Systems (ITS). Intelligent transportation systems–formerly called intelligent vehicle-highway systems (IVHS)–are information technologies that, when implemented in vehicles, on roadways, or centrally, can lead to vast savings in journey time, improved driver safety and convenience, and significant reductions in energy consumption and pollution. Among the capabilities of current and future ITS technologies are the following: 1. Traffic can be managed on the main roadways of major metropolitan areas through control of road junctions and access to major routes, rapid detection of and response to incidents (e.g., accidents and heavy congestion), and communication of advice to drivers and passengers about traffic conditions. In addition, automatic vehicle identification and toll collection open the way to variable pricing of roadway access (i.e., pricing based on road congestion). 2. A wide variety of information systems can be available to travelers (e.g., route guidance, nearby restaurants and other traveler facilities, travel time to the airport). Drivers and passengers can receive certain information by means of either eye-level “heads-up” displays or voice synthesizers installed within the vehicle. 3. Drivers can be automatically alerted to the proximity of other vehicles or obstacles. Under some advanced ITS technologies, automatic steering and intervehicle spacing control both facilitate collision avoidance and dramatically increase highway throughput. 4. Commercial vehicle operators can receive regulatory documents (e.g., permits and registrations) for multiple states in a single transaction. They can also undergo automatic weight checking without having to stop. 5. Continuous monitoring of the physical state of the road itself–as well as of bridges, tunnels, and the like–with early warnings of deterioration or structural weaknesses can be carried out through a network of probes embedded in the physical infrastructure. The enjoyment, comfort, and convenience of driving should escalate considerably as ITS systems are implemented. It is suggested that reduced stress will accrue from safety systems because of the lower probability of colliding with another vehicle. Clear directions from route guidance systems, as well as reduced congestion and travel times, will also minimize stress. Commuters will be the primary beneficiaries of these improvements, but recreational drivers will gain as well. There is an expectation, borne out by travel studies, that drivers would be willing to pay to avoid routes having unpredictable travel times. This reduction in trip duration and congestion would also alleviate stress. It is even possible that in the long run people may choose to keep their total travel time constant and increase the length of their trips to work or leisure activities, thereby gaining more options and flexibility. When combined with mass transit, ITS will enable urban and suburban travelers to make their trips on the basis of accurate, real-time information regarding travel conditions and bus and subway schedules. It will also provide them up-tothe-minute information when disruption threatens their usual routines. For example, automatic vehicle location will provide real-time information on systemwide departure times and transit vehicle locations. This information can be communicated to the transit provider and ultimately to the transit users at bus stops, shopping centers, places of employment, and other centers. Implementation of interactive communication between user and provider of transportation will occur in the final stages of advanced trip planning. Passengers will be able to make and change reservations from their homes based on realtime information regarding schedule, fares, and availability. ITS will elevate car pooling to new levels of sophistication and efficiency, which will enhance its acceptability. When automated highways are fully implemented, which is not expected to occur until well into the twenty-first century, they will result in vastly increased throughput and reduced driving fatigue. Finally, electronic driving aids will improve the quality of life for the elderly and disabled driver population by maintaining their mobility as the aging process or handicap reduces their physical abilities. The major types of traffic management systems, which have been a focal point of intelligent highway development for the past thirty years or so, are traffic-flow measuring and signal-light controlling mechanisms. Newer systems, some of which are already operational, provide (1) real-time monitoring of traffic and incidents; (2) continuous solution and optimization of problems and predicted problems, by relaying instructions to control devices; (3) signs–uniform in size, readability, and logic–that display traffic information; (4) area-wide traffic jurisdiction coordination; (5) coordination of emergency vehicles and incidents; (6) ramp metering; and (7) automatic vehicle identification/toll collection. The latter two systems offer the most potential to produce improvement in traffic flow.
Ramp metering, whereby automatic signals regulate the access of cars at the on-ramp, has been a successful technology in relieving collision risk, which research has shown increases by 150 percent when vehicles in the same traffic stream have speeds differing by more than 10 miles per hour. Where it is implemented, ramp metering has reduced freeway accidents by approximately 30 percent while substantially increasing throughput. A strategy that is frequently used in combination with ramp metering is a high-occupancy vehicle (HOV) bypass lane. This is a parallel ramp or lane reserved for HOVs that bypasses the meter. It provides an incentive for using vans and carpools.
Automatic vehicle identification (AVI), because it can provide information for such valuable functions as automated toll collection, freight tracking, and exact traffic conditions, is the segment of traffic surveillance systems that probably produces the greatest benefit. With AVI, a radio or infrared sensor at a fixed point recognizes a tag that uniquely identifies that vehicle. For toll collection, a car passes through the sensor without stopping and a computer uses the identification to debit the driver’s prepaid account, thereby relieving a potential focus of congestion. AVI also makes possible automatic road pricing or congestion pricing. This process identifies vehicles and charges tolls based on the time of day or some other variable, such as number of vehicle occupants, to control demand for roads during peak hours. These disincentives for peak-hour travel and single-occupant vehicles encourage wider use of car pooling, mass transit, and alternative work hours. Traveler information systems feed traffic and safety information to the traveler to enhance his or her traveling efficiency. This information is either stored in the vehicle itself or can be obtained by means of interactive communication with a traffic control center. Route guidance is the most prevalent application of traveler information systems. These systems are a major leap beyond the typical information currently available to drivers in their vehicles, such as vehicle speed, state of the engine, and sporadic radio reports from local stations about selected traffic and weather conditions.
Credit:ivythesis.typepad.com
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