Section B: Information Matching

Directions: In this section, you are going to read a passage with ten statements attached to it. Each statement contains information given in one of the paragraphs. Identify the paragraph from which the information is derived. You may choose a paragraph more than once. Each paragraph is marked with a letter. Answer the questions by marking the corresponding letter on Answer Sheet 2.

“Phantom” Traffic Jams Are Real—And Scientists Know How to Stop Them

[A] Traffic jams are a common problem of most big cities, either in developed or in developing countries, but one kind of traffic jams in particular can be especially frustrating. These are generally known as 'phantom' traffic jams, in which dense traffic crawls to a halt for no apparent reason at all.

[B] “When caught in such a traffic jam, it is common for drivers to assume that there must be an accident, or construction or something,” said Massachusetts Institute of Technology (MIT) computer science professor Berthold Horn. “And then you drive and drive and drive... and there isn't anything there.”

[C] The exact cause of these phantom traffic jams has long remained a mystery. But now, new research has found the cause and researchers may have come up with a solution for this frustrating traffic pattern: maintaining equal spacing between cars on the road, rather than driving so closely behind another vehicle that a collision is likely if that vehicle brakes suddenly.

[D] Horn said phantom traffic jams are an emergent property of the flow of vehicles down a highway. A phantom jam begins when a car in dense traffic slows down even slightly, which causes the car behind that vehicle to slow even more — and the slowing action spreads backward through the lane of traffic like a wave, getting worse the farther it spreads. Eventually, the cars far behind are forced to stop completely or risk hitting the slower vehicles ahead — and so the traffic grinds to a halt over nothing, Horn said.

[E] Horn has been working on the problem of phantom traffic jams for years, and he has come up with a solution: By splitting the difference between the cars in front and the cars behind, the spacing of cars in a stream of traffic can act as a damper on phantom traffic jams. That is, it can prevent the slow-down effect from being amplified by the cars that follow behind, he said. In essence, each driver would constantly make adjustments to keep their car roughly halfway between the car in front and the car behind.

[F] Horn calls this method of vehicle spacing bilateral control and he said it could be achieved with relatively simple modifications to the adaptive cruise control that many new cars already have. Adaptive cruise control is a driver assistance technology that sets a maximum speed for vehicles and automatically slows the speed of the car when traffic is sensed in front of the vehicle. The technology is also known as autonomous cruise control. Such modifications, Horn said, could help fight phantom jams within a few years, maybe decades before an alternative solution, such as networked self-driving cars, becomes a reality on the roads.

[G] Traffic jams are caused by a number of factors, such as roads that are poorly designed or over-capacity, localized factors like city traffic-lighting patterns, and events like accidents and construction. But phantom traffic jams can make all those problems worse, Horn said. And the researchers in the new study have calculated that solving phantom jams could save at least some of the estimated $121 billion per year that traffic jams are estimated to cost the U.S. economy, Horn told Live Science.

[H] New research by Horn and MIT postdoctoral associate Liang Wang, published in the journal IEEE Transactions on Intelligent Transportation Systems, shows how bilateral control can fight the problem. The researchers made computer models of real-world traffic conditions, showing how a typical U.S. freeway could benefit from cars using bilateral control. That would be in place when human drivers fail to slow down, thus avoiding tailgating the car in front, Horn said. “Under reasonable conditions today, you might get 1,800 cars per lane per hour throughput,” he added. “But with bilateral control you could almost double that.”

[I] The main alternative to increasing traffic throughput per lane has been to build more lanes and more highways, and putting in new roads is very expensive, he said. “If we can increase the throughput on major highways, even if it's only by 50 percent that would be a big deal,” Horn said.

[J] With the help of engineering students at high schools in Maine, Horn and Wang have also built a robot simulation that shows how bilateral control can suppress phantom traffic jams. Increasing the spacing of vehicles dampens the effect of slowdowns by cars in front of a given car, so that the slowing is not worsened until it becomes a phantom jam, the researchers said.

[K] A video from the project shows a train of autonomous robots running along a track without bilateral control: they eventually back up in phantom jams. But when the robots are switched over to bilateral control (by flashing the lights in the room), each autonomous robot tries to keep itself halfway between the robot in front and the one behind; the phantom jams disappear as a result, Horn said.

[L] Since starting his research on phantom traffic jams, Horn has learned that schools of fish and flocks of birds and bats use similar spacing strategies to avoid hitting each other while swimming or flying in densely packed groups. In particular, studies of millions of bats emerging at dusk from caves in Southeast Asia showed that each bat used a form of bilateral control to reduce the likelihood of collisions with other bats in the densely packed swarm, Horn said.

[M] Unlike bats, birds and fish, however, humans have difficulty judging distances behind them. To address that weakness, Horn is now working with the car company Toyota to enable a form of bilateral control via modifications to existing adaptive cruise control systems, which use forward-facing sensors to judge the distance to the vehicle ahead. The bilateral control approach would include adding rear-facing sensors to determine the distance to the vehicle following a car.

[N] But until those systems become standard, human drivers can help reduce phantom traffic jams simply by not following the car in front so closely. As Horn argues, “There's absolutely no advantage of tailgating the car in front of you.”

36. The age-long mystery has now been resolved as to how phantom traffic jams are caused.

37. It is possible to nearly double the hourly throughput per lane by adopting bilateral control.

38. According to Horn, drivers making constant adjustments for equal spacing between cars in a flow of traffic can help reduce phantom traffic jams.

39. Before systems for bilateral control are installed, drivers should not follow the car in front too closely so as to reduce phantom traffic jams.

40. Horn said with some simple modifications to the existing equipment in new vehicles, their spacing bilateral control could be accomplished.

41. Drivers caught up in phantom traffic jams are likely to think an accident has happened or some construction is going on.

42. Two sets of sensors would be used to help drivers determine the distances between cars.

43. Solving the problem of phantom jams could save America billions of dollars every year.

44. In a phantom traffic jam, the cars in the same lane slow down one after another, creating a wave-like effect.

45. Horn has found that certain creatures use strategies similar to bilateral control to avoid hitting each other while moving in dense crowds.

Answers & Explanations

36. C。解析：题干中的 age-long mystery has now been resolved as to how phantom traffic jams are caused（关于幽灵堵车原因的长久谜团现在已经解开）对应 [C] 段的 The exact cause of these phantom traffic jams has long remained a mystery. But now, new research has found the cause...（幽灵堵车的确切原因长久以来一直是个谜。但是现在，新研究发现了原因...）。age-long mystery 对应 long remained a mystery，resolved 对应 found the cause。

37. H。解析：题干中的 nearly double the hourly throughput per lane（每车道每小时的吞吐量几乎翻倍）对应 [H] 段的 you might get 1,800 cars per lane per hour throughput... But with bilateral control you could almost double that（在如今合理的条件下，你可以获得每车道每小时1800辆车的吞吐量...但是有了双边控制，你几乎可以让吞吐量翻倍）。nearly double 对应 almost double。

38. E。解析：题干中的 making constant adjustments for equal spacing between cars（不断调整以保持车辆之间的等距）对应 [E] 段的 each driver would constantly make adjustments to keep their car roughly halfway between the car in front and the car behind（每个司机都会不断调整，使自己的车大致保持在前后车中间）。equal spacing 同义替换为 halfway between。

39. N。解析：题干中的 Before systems... are installed, drivers should not follow the car in front too closely（在安装系统之前，司机不应跟前车太近）对应 [N] 段的 But until those systems become standard, human drivers can help reduce phantom traffic jams simply by not following the car in front so closely（但在这些系统成为标准配置之前，人类司机可以简单地通过不紧跟前车来帮助减少幽灵堵车）。Before... are installed 对应 until those systems become standard。

40. F。解析：题干中的 simple modifications to the existing equipment in new vehicles... bilateral control could be accomplished（对新车现有设备进行一些简单的修改，就可以实现双边控制）对应 [F] 段的 he said it could be achieved with relatively simple modifications to the adaptive cruise control that many new cars already have（他说，只要对许多新车已经配备的自适应巡航控制系统进行相对简单的修改，就可以实现这一点）。existing equipment 对应 adaptive cruise control that many new cars already have，accomplished 对应 achieved。

41. B。解析：题干中的 Drivers caught up in phantom traffic jams are likely to think an accident has happened or some construction is going on（陷入幽灵堵车的司机很可能会认为发生了事故或正在施工）对应 [B] 段的 When caught in such a traffic jam, it is common for drivers to assume that there must be an accident, or construction...（当陷入这种交通堵塞时，司机通常会认为一定发生了事故，或者在施工...）。likely to think 对应 assume。

42. M。解析：题干中的 Two sets of sensors would be used to help drivers determine the distances between cars（将使用两套传感器帮助驾驶员确定车距）对应 [M] 段的 which use forward-facing sensors to judge the distance... include adding rear-facing sensors to determine the distance...（使用前向传感器判断距离...包括增加后向传感器来确定距离...）。Two sets of sensors 对应 forward-facing sensors 和 rear-facing sensors。

43. G。解析：题干中的 could save America billions of dollars every year（每年可以为美国节省数十亿美元）对应 [G] 段的 solving phantom jams could save at least some of the estimated $121 billion per year that traffic jams are estimated to cost the U.S. economy（解决幽灵堵车问题可以节省交通堵塞给美国经济造成的每年约1210亿美元损失中的一部分）。save America billions of dollars 对应 save... $121 billion... U.S. economy。

44. D。解析：题干中的 cars in the same lane slow down one after another, creating a wave-like effect（同一车道上的汽车一辆接一辆地减速，产生波浪效应）对应 [D] 段的 the slowing action spreads backward through the lane of traffic like a wave（减速行为像波浪一样在车道上向后蔓延）。

45. L。解析：题干中的 Horn has found that certain creatures use strategies similar to bilateral control to avoid hitting each other while moving in dense crowds（Horn发现某些生物使用类似于双向控制的策略，以避免在密集的群体中移动时互相撞击）对应 [L] 段的 schools of fish and flocks of birds and bats use similar spacing strategies to avoid hitting each other while swimming or flying in densely packed groups（鱼群、鸟群和蝙蝠使用相似的间距策略，以避免在密集移动时撞到对方）。certain creatures 对应 fish and flocks of birds and bats，dense crowds 对应 densely packed groups。

核心搭配与高分句型

【核心搭配与高频短语】

• crawl to a halt：缓慢移动直到停止（dense traffic crawls to a halt）
• come up with：想出，提出（come up with a solution）
• an emergent property：涌现特性，突发属性（an emergent property of the flow of vehicles）
• grind to a halt：慢慢停下来（traffic grinds to a halt）
• split the difference：折中，平分差额（By splitting the difference between...）
• act as a damper on：起到减震器/抑制因素的作用（act as a damper on phantom traffic jams）
• back up：倒退，（交通）堵塞（they eventually back up in phantom jams）
• pass off as：伪装成，冒充（注：此处引用词库里的其他短语备考，本文类似表达是 `pose as`）

【亮点句型解析】

• The + 比较级..., the + 比较级... 句型：
  "...the slowing action spreads backward through the lane of traffic like a wave, getting worse the farther it spreads."
  （...减速行为像波浪一样沿着车道向后蔓延，蔓延得越远情况就越糟。）前半句使用了比喻（like a wave）生动描述了减速的传递过程，后半句 `getting worse the farther it spreads` 等同于 `the farther it spreads, the worse it gets`，表示程度随距离加深，是四六级写作中的加分句型。
• Wh- 词 + 介词 + 动名词短语 (介词宾语从句的简化)：
  "Since starting his research on phantom traffic jams, Horn has learned that schools of fish and flocks of birds and bats use similar spacing strategies to avoid hitting each other while swimming or flying in densely packed groups."
  （自从开始研究幽灵堵车以来，Horn了解到...）`while swimming or flying` 是 `while they are swimming or flying` 的省略结构，做时间状语，使得句子结构紧凑、高级。这种在从句中省略主语和 be 动词的用法在学术英语中极为常见。