文章来源:未知 文章作者:enread 发布时间:2012-12-24 06:36 字体: [ ]  进入论坛
In most cities, traffic growth has outpaced road capacity, leading to increased congestion1(拥挤), particularly during the morning and evening commutes2. In 2007, congestion on U.S. roads was responsible for 4.2 billion hours of additional travel time, as well as 2.8 billion gallons of fuel consumption and an accompanying increase in air pollution. One way to prevent traffic tie-ups is to have fewer cars on the road by encouraging alternatives such as public transportation, carpooling(合伙用车), flex3 time(弹性时间) and working from home. But a new study -- by researchers at MIT, Central South University in China, the University of California at Berkeley and the Austrian Institute of Technology -- incorporates data from drivers' cellphones to show that the adoption4 of these alternatives by a small percentage of people across a metropolitan5 area might not be very effective. However, if the same number of people, but from a carefully selected segment of the driving population, chooses not to drive at rush hour, this could reduce congestion significantly.
The study, published in the Dec. 20 issue of the journal Scientific Reports, demonstrates that canceling or delaying the trips of 1 percent of all drivers across a road network would reduce delays caused by congestion by only about 3 percent. But canceling the trips of 1 percent of drivers from carefully selected neighborhoods would reduce the extra travel time for all other drivers in a metropolitan area by as much as 18 percent.
"This has an analogy in many other flows in networks," says lead research Marta González, the Gilbert W. Winslow Career Development Assistant Professor in MIT's Department of Civil and Environmental Engineering. "Being able to detect and then release the congestion in the most affected6 arteries7 improves the functioning of the entire coronary system."
The study, designed by González and former MIT postdoc Pu Wang, now a professor at Central South University, is the first large-scale traffic study to track travel using anonymous8 cellphone data rather than survey data or information obtained from U.S. Census9 Bureau travel diaries. Both of these are prone10 to error because of the time lag between gathering11 and releasing data and the reliance on self-reporting.
González and Wang used three weeks of cellphone data to obtain information about anonymous drivers' routes and the estimated traffic volume and speed on those routes. They inferred a driver's home neighborhood from the regularity12 of the route traveled and from the locations of cell towers that handled calls made between 9 p.m. and 6 a.m. They combined this with information about population densities13 and the location and capacity of roads in the networks of two metropolitan areas -- Boston and San Francisco -- to determine which neighborhoods are the largest sources of drivers on each road segment, and which roads these drivers use to connect from home to highways and other major roadways.


1 congestion pYmy3     
  • The congestion in the city gets even worse during the summer.夏天城市交通阻塞尤为严重。
  • Parking near the school causes severe traffic congestion.在学校附近泊车会引起严重的交通堵塞。
2 commutes 3547de72fa26e075391aeef6adf7f98a     
上下班路程( commute的名词复数 )
  • She commutes from Oxford to London every day. 她每天上下班往返于牛津与伦敦之间。
  • Barbara lives in Oxford and commutes. 芭芭拉住在牛津,通勤往来。
3 flex Cjwxc     
  • We wound off a couple of yards of wire for a new lamp flex.我们解开几码电线作为新的电灯花线。
  • He gave his biceps a flex to impress the ladies.他收缩他的肱二头肌以吸引那些女士们的目光。
4 adoption UK7yu     
  • An adoption agency had sent the boys to two different families.一个收养机构把他们送给两个不同的家庭。
  • The adoption of this policy would relieve them of a tremendous burden.采取这一政策会给他们解除一个巨大的负担。
5 metropolitan mCyxZ     
  • Metropolitan buildings become taller than ever.大城市的建筑变得比以前更高。
  • Metropolitan residents are used to fast rhythm.大都市的居民习惯于快节奏。
6 affected TzUzg0     
  • She showed an affected interest in our subject.她假装对我们的课题感到兴趣。
  • His manners are affected.他的态度不自然。
7 arteries 821b60db0d5e4edc87fdf5fc263ba3f5     
n.动脉( artery的名词复数 );干线,要道
  • Even grafting new blood vessels in place of the diseased coronary arteries has been tried. 甚至移植新血管代替不健康的冠状动脉的方法都已经试过。 来自《简明英汉词典》
  • This is the place where the three main arteries of West London traffic met. 这就是伦敦西部三条主要交通干线的交汇处。 来自《简明英汉词典》
8 anonymous lM2yp     
  • Sending anonymous letters is a cowardly act.寄匿名信是懦夫的行为。
  • The author wishes to remain anonymous.作者希望姓名不公开。
9 census arnz5     
  • A census of population is taken every ten years.人口普查每10年进行一次。
  • The census is taken one time every four years in our country.我国每四年一次人口普查。
10 prone 50bzu     
  • Some people are prone to jump to hasty conclusions.有些人往往作出轻率的结论。
  • He is prone to lose his temper when people disagree with him.人家一不同意他的意见,他就发脾气。
11 gathering ChmxZ     
  • He called on Mr. White to speak at the gathering.他请怀特先生在集会上讲话。
  • He is on the wing gathering material for his novels.他正忙于为他的小说收集资料。
12 regularity sVCxx     
  • The idea is to maintain the regularity of the heartbeat.问题就是要维持心跳的规律性。
  • He exercised with a regularity that amazed us.他锻炼的规律程度令我们非常惊讶。
13 densities eca5c1ea104bef3058e858fe084fb6d0     
密集( density的名词复数 ); 稠密; 密度(固体、液体或气体单位体积的质量); 密度(磁盘存贮数据的可用空间)
  • The range of densities of interest is about 3.5. 有用的密度范围为3.5左右。
  • Densities presumably can be probed by radar. 利用雷达也许还能探测出气体的密度。
TAG标签: traffic time travel