TRAFFIC JAM
When I live in Bangkok I think it very busy and traffic jam the cause There are severalmain causes of traffic congestion. The prime cause is simply a volume of traffic or modalsplit that generates demand for space greater than the road capacity, but there are a numberospecific circumstances which cause or aggravate congestion - most of which reduce the capacityof a road at a given point or over a certain length, or increase the number of vehicles requiredfora given throughput of people or goods. The former causes include on-road parking, constructionworks, accidents and emergencies or unsafe road conditions (due to weather or other factors)thelatter causes include conditions where the mode share between high and low occupancy vehiclesprimarily consists of low occupancy vehicles or of types of vehicle that take up a large quantumof network space per person. 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 which then spread out and create a sustained traffic jam when otherwise, normal flow might have continued for some time longer. Mathematical theories Traffic engineers therefore 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 supercooled fluid. In the three phase traffic theory of Boris Kerner, congestion is classified into two distinct phases: synchronised flow and wide moving jams (in addition to the first phase, free flow). In synchronised flow, the speeds of the vehicles are low and vary quite a lot between vehicles, but the traffic flow (expressed in vehicles per time unit) remains close to free flow. In wide moving jams, vehicle speeds are more equal and lower, and time delays can be quite large. 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-utilize 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 roadworks, 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), offers a dissenting view: 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 queueing (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 therefrom into public transportation projects. Road pricing itself is controversial, more information is available in the dedicated article. Classification Qualitative classification of traffic is often done in the form of a six letter A-F level of service (LOS) scale defined in the Highway Capacity Manual, a US document used (or used as a basis for national guidelines) worldwide. These levels are used by transportation engineers as a shorthand and to describe traffic levels to the lay public. While this system generally uses delay as the basis for its measurements, the particular measurements and statistical methods vary depending on the facility being described. For instance, while the percent time spent following a slower-moving vehicle figures into the LOS for a rural two-lane road, the LOS at an urban intersection incorporates such measurements as the number of drivers forced to wait through more than one signal cycle.
Negative impacts I Think
- 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, education etc. - 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 increases air pollution owing to increased idling, acceleration and braking. Increased fuel use may also in theory cause an imperceptible 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 which may affect neighborhood amenity and real estate prices
I think Bangkok is not good because have many problem thank you teacher
ไม่มีความคิดเห็น:
แสดงความคิดเห็น