交通信号研究外文文献翻译中英文

1、交通信号研究外文文献翻译 (含：英文原文及中文译文) 文献出处： vehicular technology ieee transactions on, 2012, 3(1):8-16.英文原文 traffic signalsroozemond jeanin the united states alone ,some 250,000 intersections have traffic signals , which are defined as all power-operated traffic-control devices except flashers, signs , and mar

2、kings for directing or warning motorists, cyclists, or pedestrians.signals for vehicular , bicycle , and pedestrian control are pretimed where specific times intervals are allocated to the various traffic movements and as traffic actuated where time intervals are controlled in whole or in part by tr

3、affic demand.pretimed traffic signalspretimed traffic signals are set to repeat regularly a given sequence of signal indications for stipulated time intervals through the 24-hr day. they have the advantages of having controllors of lower first cost and that they can be interconnected and coordinated

4、 to vehicles to move through a series of intersections with a minimum of stops and other delays.also, their operation is unaffected by conditions brought on by unusual vehicle behavior such as forced stops, which , with some traffic-actuated signal installations may bring a traffic jam. their disadv

5、antage is that they cannot adjust to short-time variations in traffic flow and often hold vehicles from one direction when there is no traffic in the other. this results in inconvenience, and sometimes a decrease in capacity. cycle length the time required for a complete sequence of indications, ord

6、inarily falls between 30 and 120s. short cycle lengths are to be preferred, as the delay to standing vehicles is reduced. with short cycles, however a relatively high percentage of the total time is consumed in clearing the intersection and starting each succeeding movement. as cycle length increase

7、s, the percentage of time lost from these causes decreases. with high volumes of traffic, it may be necessary to increase the cycle length to gain added capacity.each traffic lane of a normal signalized intersection can pass roughly one vehicle each 2.1s of green light. the yellow (caution) interval

8、 following each green period is usually between 3 and 6s, depending on street width, the needs of pedestrians, and vehicle approach speed. to determine an approximate cycle division, it is common practice to make short traffic counts during the peak period. simple computations give the number of veh

9、icles to be accommodated during each signal indication and the minimum green time required to pass them. with modern control equipment, it is possible to change the cycle length and division several times a day, or go to flashing indications to fit the traffic pattern better.at many intersections, s

10、ignals must be timed to accommodate pedestrian movements. the manual recommends that the minimum total time allowed be an initial interval of 4 to 7s for pedestrians to start plus walking time computed at 4 ft/s (1. 2m/s). with separate pedestrian indicators, the walk indication(lunar white) covers

11、the first of these intervals, and flashing dont walk (portland orange ) the remainder. the walk signal flashes when there are possible conflicts with vehicles and is steady when there are none. steady dont walk tells the pedestrian not to proceed.if pedestrian control is solely by the vehicle signal

12、s, problems develop if the intersection is wide, since the yellow clearance interval will have to be considerably longer than the 3 to 5s needed by vehicles. this will reduce intersection capacity and may call for a longer cycle time. on wide streets having a median at least 6 ft (1. 8m)wide, pedest

13、rians may be stopped there. a separate pedestrian signal activator must be placed on this median if pedestrian push buttons are incorporated into the overall control system.coordinated movementfixed-time traffic signals along a street or within an area usually are coordinated to permit compact group

14、s of vehicles called platoons to move along together without stopping. under normal traffic volumes, properly coordinated signals at intervals variously estimated from 2500 ft (0. 76km)to more than a mile (1. 6km) are very effective in producing a smooth flow of traffic. on the other hand, when a st

15、reet is loaded to capacity, coordination of signals is generally ineffective in producing smooth traffic flow.four systems of coordination-simultaneous, alternate, limited progressive, and flexible progressive-have developed over time. the simultaneous system made all color indications on a given st

16、reet alike at the same time .it produced high vehicle speeds between stops but low overall speed. because of this and other faults, it is seldom used today.the alternate system has all signals change their indication at the same time, but adjacent signals or adjacent groups of signals on a given str

17、eet show opposite colors. the alternate system works fairly well on a single street that has approximately equal block spacing. it also has been effective for controlling traffic in business districts several blocks on a said, but only when block lengths are approximately equal in both directions. w

18、ith an areawide alternate system , green and red indications must be of approximately equal length. this cycle division is satisfactory where two major streets intersect but gives too much green time to minor streets crossing major arteries. other criticisms are that at heavy traffic volumes the lat

19、er section of the platoon of vehicles is forced to make additional stops, and that adjustments to changing traffic conditions are difficult.the simple progressive system retains a common cycle length but provides go indications separately at each intersection to match traffic progression. this permi

20、ts continuous or nearly continuous flow of vehicle groups at a planned speed in at least one direction and discourages speeding between signals. flashing lights may be substituted for normal signal indications when traffic becomes light.the flexible progressive system has a master controller mechani

21、sm that directs the controllers for the individual signals. this arrangement not only gives positive coordination between signals , but also makes predetermined changes in cycle length , cycle split , and offsets at intervals during the day. for example, the cycle length of the entire system can be

22、lengthened at peak hours to increase capacity and shortened at other times to decrease delays. flashing indications can be substituted when normal signal control is not needed. also the offsets in the timing of successive signals can be adjusted to favor heavy traffic movements, such as inbound in t

23、he morning and outbound in the evening. again, changes in cycle division at particular intersections can be made. the traffic responsive system is an advanced flexible progressive system with the capacity to adjust signal settings to measured traffic volumes.where traffic on heavy-volume or high-spe

24、ed arteries must be interrupted for relatively light cross traffic, semi-traffic-actuated signals are sometimes used. for them, detectors are placed only on the minor street. the signal indication normally is green on the main road and red on the cross street. on actuation, the indications are rever

25、sed for an appropriate interval after which they return to the original colors.the quality of urban traffic control systems is determined by the match between the control schema and the actual traffic patterns. if traffic patterns change what they usually do the effectiveness is determined by the wa

26、y in which the system adapts to these changes. when this ability to adapt becomes an integral part of the traffic control unit it can react better to changes in traffic conditions. adjusting traffic control unit is a costly and timely affair if it involves human attention. the hypothesis is that it

27、might offer additional benefit using self-evaluating and self-adjusting traffic control systems. there is already a market for an urban traffic control system that is able to react if the environment changes the so called adaptive systems. quot racquet adaptive systems will need pro-active calculate

28、d traffic information and cycle plans- based on these calculated traffic conditions- to be updated frequently. our research of the usability of agent technology within traffic control can be split into two parts. first there is a theoretical part integrating agent technology and traffic control. the

29、 final stage of this research focuses on practical issues like implementation and performance. here we present the concepts of agent technology applied to dynamic traffic control. currently we are designing a layered model of an agent based urban traffic control system. we will elaborate on that in

30、the last chapters.these agents have the task of solving conflicts between lower level agents that they cant solve. this represents current traffic control implementations and ideas. one final aspect to be mentioned is the robustness of agent based systems if all communication fails the agent runs on

31、 if the agent fails a fixed program can be executed. to be able to keep our first urban traffic control model as simple as possible weave made the following assumptions: we limit ourselves to inner city traffic control road segments intersections corridors we handle only controlled intersections wit

32、h detectors intensity and speed at all road segments we only handle cars and we use simple rule bases for knowledge representation. types of agents in urban intersection control as we divide the system in several recognizable parts we define the following 4types of agents:- roads are represented by

33、special road segment agents rsa- controlled intersections are represented by intersection agents itsa- for specific defined areas there is an area agent higher level- for specific routes there can be route agents that spans several adjoining road segments higher level. we have not chosen for one age

34、nt per signal. this may result in a more simple solution but available traffic control programs do not fit in that kind of agent. we deliberately choose a more complex agent to be able to use standard traffic control design algorithms and programs. the idea still is the optimization on a local level

35、 intersection but with local and global control. therefore we use area agents and route agents. all communication takes place between neighboring agents and upper and lower level ones. design of our agent based system the essence of a demand responsive and pro-active agent based utc consists of seve

36、ral itsas intersection agent. some authority agents area and route agents and optional road segment agents rsa. the itsa makes decisions on how to control its intersection based on its goals capability knowledge perception and data. when necessary an agent can request for additional information or r

37、eceive other goals or orders from its authority agents. for a specific itsa implemented to serve as an urban traffic control agent the following actions are incorporated rosemont 1998:- data collection / distribution via rsa - information on the current state of traffic from / to other itsas - on ot

38、her adjoining signalized intersections- analysis with an accurate model of the surrounds and knowing the traffic and traffic control rules define current trend detect current traffic problems- calculation calculate the next optimal cycle mathematically correct- decision making with other agent decid

39、ing what to use for next cycle handle current traffic problems- control operate the signals according to cycle plan. in figure 1 a more specific example of a simplified agent based utc system is given. here we have a route agent controlling several intersection agents which in turn manage their inte

40、rsection controls helped by rsas. the itsa is the agent that controls and operates one specific intersection of which it is completely informed. allits as have direct communication with neighboring itsas rsas and all its traffic lights. here we use the agent technology to implement a distributed pla

41、nning algorithm.中文译文交通信号研究作者：roozemond jean仅在美国，大约有25万个十字路口设有交通信号灯，交通信号灯定义为除了闪光灯，标志和指示或警告驾驶者，骑自行车者或行人的标志之外的所有动力操作交通控制设备。用于车辆，自行车和行人控制的信号是“预先计划好的”，其中特定的时间间隔分配给各种交通流动，并且作为“交通启动”，其中时间间隔全部或部分由交通需求控制。预先制定的交通信号“预定”交通信号设置为在24小时的日期内按规定的时间间隔定期重复给定的信号指示序列。它们具有控制成本较低的优点，并且可以与车辆相互联系和协调，以最少的停车时间和其他延迟通过一系列交叉路口。此外

42、，它们的运行不会受到异常车辆行为（如强制停车）带来的情况的影响，这些情况下，一些交通驱动的信号装置可能会造成交通堵塞。他们的缺点是他们无法适应短时间的交通流量变化，并且通常在另一个方向没有交通时从一个方向控制车辆。这导致不便，并且有时会降低容量。“周期长度”是指示完整顺序所需的时间，通常在30到120秒之间。较短的循环长度是优选的，因为延迟站立的车辆减少。在周期较短的情况下，相对较高的总时间百分比用于清除交叉点并开始每个后续运动。随着周期长度的增加，由这些原因造成的时间损失百分比下降。由于流量大，可能需要增加周期以增加容量。正常信号交叉口的每个车道可以通过大约一个车辆，每个2.1s的绿灯。每个

43、绿色周期后的黄色（警示）间隔通常在3到6秒之间，取决于街道宽度，行人需求和车辆接近速度。为了确定一个近似的周期划分，通常的做法是在高峰期进行短时间的流量统计。简单的计算给出了在每个信号指示期间要容纳的车辆数量以及通过它们所需的最短绿色时间。使用现代化的控制设备，可以每天更改几次循环长度和分区，或者更快地闪烁以适应交通模式。在许多交叉路口，信号必须定时以适应行人的移动。 “手册”建议允许的最短总时间为行人开始加步行时间的初始间隔为4至7秒，计算时间为4英尺/秒（1.2米/秒）。通过独立的行人指示灯，walk指示（月亮白色）涵盖了这些间隔中的第一个，其余部分闪烁着不要行动（波特兰橙色）。 walk

44、信号在与车辆可能发生冲突时闪烁，没有时会稳定。坚定不要行动告诉行人不要进行。如果行人控制完全依靠车辆信号，那么如果交叉路口较宽，则会出现问题，因为黄色间隙必须比车辆需要的3-5秒长得多。这将减少路口通行能力，并可能需要更长的周期时间。在中间宽度至少为6英尺（1.8米）的宽阔街道上，行人可能会停在那里。如果在整个控制系统中集成了行人按钮，则必须在这个中间位置放置一个单独的行人信号激励器。协调运动沿着街道或区域内的固定时间交通信号通常会进行协调，以允许称为“排”的紧凑型车辆在不停车的情况下一起移动。在正常交通量的情况下，以2500英尺（0.76公里）至超过1.6英里（1.6公里）的各种间隔进行适当

45、的协调信号对于产生平稳的交通流量非常有效。另一方面，当一条街道满负荷运转时，信号的协调一般无法有效地产生畅通的交通流量。随着时间的推移，四种系统的协调 - 同步，交替，有限的渐进式和灵活的渐进 - 已经发展起来。同步系统同时在给定的街道上进行了所有颜色指示。它在停车间产生了较高的车速，但整体速度较低。由于这个和其他故障，它今天很少使用。备用系统的所有信号同时改变其指示，但是在给定街道上的相邻信号或相邻信号组显示相反的颜色。在具有大致相等的块间距的单个街道上，替代系统工作得很好。它也有效地控制了商业区的交通量，但只有在两个方向上的路段长度大致相等时才是如此。在区域范围内的替代系统中，绿色和红色指

46、示必须大致相等。在两条主要街道交叉的地方，这种周期划分是令人满意的，但是对于通过主要动脉的小街道来说，这种周期划分的时间太长。其他批评指出，在交通繁忙的情况下，后排排队车辆将被迫增加停车位，并且对交通状况变化的调整很困难。简单的渐进式系统保留了一个通用的周期长度，但在每个路口分别提供“走”指示以匹配交通流量。这允许车辆组在至少一个方向上以计划速度连续或几乎连续地流动，并且阻止信号之间的超速。当交通变浅时，闪烁的灯可能代替正常的信号指示。灵活的渐进式系统具有一个主控制器机制，可以将控制器指向各个信号。这种布置不仅给出了信号之间的正向协调，而且还在一天中的间隔中对周期长度，周期分割和偏移进行了预定的改变。例如，整个系统的周期长度可以在高峰时间延长以增加容量并在其他时间缩短以减少延迟。当不需要正常信号控制时，闪烁指示可被替代。此外，可以调整连续信号的时间偏移以支持繁忙的交通运动，例如早上入站和晚上出站。再次，可以对特定交叉点处的周期划分进行改变。交通响应系统是一个先进的灵活的渐进式系统