盡管(guan)你可能(neng)會咒罵每一個(ge)紅燈，城(cheng)市規劃者確實試圖使交(jiao)通(tong)信號(hao)同(tong)步化以改善交(jiao)通(tong)，他們甚(shen)至依靠超級計算機來設計最佳方案(an)。交(jiao)通(tong)信號(hao)燈在交(jiao)通(tong)高峰期間保持綠色(se)的時(shi)間要(yao)長(chang)一些，計算機模型幫助(zhu)使公共交(jiao)通(tong)享受優先待遇。但是諸如(ru)十字(zi)路口的步行者、大量(liang)人群和車輛等變量(liang)使仔細設計的系統(tong)出錯，導(dao)致令人惱(nao)火并(bing)造成污染的交(jiao)通(tong)擁(yong)堵(du)。

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　　德國德累斯頓工科(ke)大學(xue)教授(shou)(shou)斯蒂芬-拉米爾(er)、在新墨西哥州(zhou)圣菲研究所工作的蘇黎世教授(shou)(shou)德克-赫爾(er)賓稱，一個具有自我組織(zhi)能力的交通信號燈系統將取得(de)更好的效(xiao)果(guo)。

　　他們建(jian)立了一個(ge)把交通(tong)視(shi)為液體、交通(tong)路(lu)口(kou)(kou)視(shi)為管網的(de)(de)(de)模型。他們隨后給每(mei)個(ge)信(xin)(xin)號燈安裝一個(ge)感(gan)應(ying)裝置，感(gan)應(ying)裝置將(jiang)提(ti)供(gong)任何(he)一個(ge)特(te)定時(shi)刻的(de)(de)(de)交通(tong)信(xin)(xin)息。燈光內的(de)(de)(de)計算機芯片計算車輛流(liu)，確定燈保持(chi)綠(lv)色的(de)(de)(de)時(shi)間長度。但這種(zhong)(zhong)每(mei)個(ge)信(xin)(xin)號燈只處理(li)自(zi)身情況的(de)(de)(de)“叢林(lin)原則”并不能(neng)導致和睦情況的(de)(de)(de)出現。解(jie)決方案是采(cai)用非中心處理(li)的(de)(de)(de)方案，讓信(xin)(xin)號燈進行(xing)合作，確定每(mei)個(ge)路(lu)口(kou)(kou)的(de)(de)(de)變化將(jiang)如何(he)影響整個(ge)系統。這種(zhong)(zhong)非周期性的(de)(de)(de)方法將(jiang)可以解(jie)決一個(ge)尤其令人惱火的(de)(de)(de)現象：在沒有其它車輛時(shi)，卻要止步(bu)于紅燈前。

　　拉米爾和拉爾賓在一(yi)個計算機(ji)模擬的(de)德(de)累斯頓市中心測試了(le)(le)他(ta)們的(de)算法，發現交(jiao)通等待時(shi)間縮小了(le)(le)百(bai)分之十至百(bai)分之三(san)十。

　　Giving Traffic Lights a Mind of Their Own Can Reduce Congestion

　　A system of self-organizing traffic lights could reduce congestion, according to European researchers. The key is allowing lights to switch from green to red in a decentralized, chaotic way, instead of following a regular programmed pattern。

　　Though you might curse them at every red light, city planners do try to synchronize traffic signals to improve flow, even relying on supercomputers to design the optimal patterns. Lights stay green longer during peak traffic hours, and computer models help prioritize public transit. But variables like pedestrians in crosswalks, large crowds and vehicle wrecks can throw a carefully designed system out of whack, leading to annoying and pollution-causing traffic jams。

　　Stefan L?mmer, a professor at Dresden University of Technology in Germany, and Dirk Helbing, a professor in Zurich, Switzerland, who works with the Santa Fe Institute in New Mexico, say a s[FS:PAGE]elf-organizing system would work better。

　　They started by modeling traffic as if it were a fluid, comparing intersections to a network of pipes. Then they gave each traffic signal a sensor that provides information about traffic at a given moment. Computer chips in the lights calculate the expected flow of vehicles, and determine how long the lights should stay green。

　　But this “jungle principle” of every light for itself does not result in harmony, the researchers said. If each traffic light responds to its immediate demands, then all the lights will just react to the traffic coming from nearby intersections, which defeats the purpose of a smart network。

　　The solution is a decentralized approach that lets the traffic lights work together by figuring out how changes at each inpidual intersection would affect the entire system. Instead of being stymied by natural fluctuations in traffic, the system takes advantage of them, using random gaps to help improve traffic flow. Traffic lights could request green time only when there is a definite demand for them, the researchers write. This acyclic approach could eliminate the particularly annoying problem of sitting at a red light while there’s no traffic。

　　L?mmer and Helbing tested tested their algorithms in a computer-simulated version of the city center of Dresden, and found delay times could be reduced from 10 to 30 percent. Their paper doesn’t mention road rage, but if the system works, it’s safe to assume reductions there, too。