交通信號燈是(shi)指揮交通(tong)(tong)運行(xing)的信號燈(deng)，一般(ban)由紅(hong)燈(deng)、綠燈(deng)、黃燈(deng)組(zu)成。紅(hong)燈(deng)表示(shi)禁止通(tong)(tong)行(xing)，綠燈(deng)表示(shi)準許(xu)通(tong)(tong)行(xing)，黃燈(deng)表示(shi)警示(shi)。

    交(jiao)通(tong)信號燈(deng)分為(wei)：機動車(che)信號燈(deng)、非機動車(che)信號燈(deng)、人行橫道信號燈(deng)、方向指(zhi)示指(zhi)示燈(deng)（箭頭(tou)信號燈(deng)）、車(che)道信號燈(deng)、閃光警告(gao)信號燈(deng)、道路與鐵路平面交(jiao)叉道口(kou)信號燈(deng)。

    在十字(zi)路(lu)口(kou)，四面(mian)都(dou)懸掛著紅(hong)(hong)(hong)、黃(huang)、綠(lv)(lv)、三色交(jiao)通(tong)(tong)信(xin)(xin)號(hao)(hao)燈(deng)(deng)(deng)(deng)，它是(shi)(shi)不出聲(sheng)的(de)(de)“交(jiao)通(tong)(tong)警察(cha)”。紅(hong)(hong)(hong)綠(lv)(lv)燈(deng)(deng)(deng)(deng)是(shi)(shi)國際(ji)統一的(de)(de)交(jiao)通(tong)(tong)信(xin)(xin)號(hao)(hao)燈(deng)(deng)(deng)(deng)。紅(hong)(hong)(hong)燈(deng)(deng)(deng)(deng)是(shi)(shi)停(ting)止信(xin)(xin)號(hao)(hao)，綠(lv)(lv)燈(deng)(deng)(deng)(deng)是(shi)(shi)通(tong)(tong)行(xing)信(xin)(xin)號(hao)(hao)。交(jiao)叉路(lu)口(kou)，幾個方向(xiang)來的(de)(de)車(che)都(dou)匯集在這(zhe)兒，有(you)的(de)(de)要(yao)(yao)直行(xing)，有(you)的(de)(de)要(yao)(yao)拐彎(wan)(wan)，到底讓(rang)誰先(xian)走，這(zhe)就(jiu)是(shi)(shi)要(yao)(yao)聽從紅(hong)(hong)(hong)綠(lv)(lv)燈(deng)(deng)(deng)(deng)指揮。紅(hong)(hong)(hong)燈(deng)(deng)(deng)(deng)亮(liang)，禁止直行(xing)或(huo)(huo)左轉彎(wan)(wan)，在不礙行(xing)人和車(che)輛情(qing)況下，允許(xu)(xu)車(che)輛右(you)轉彎(wan)(wan)；綠(lv)(lv)燈(deng)(deng)(deng)(deng)亮(liang)，準許(xu)(xu)車(che)輛直行(xing)或(huo)(huo)轉彎(wan)(wan)；黃(huang)燈(deng)(deng)(deng)(deng)亮(liang)，停(ting)在路(lu)口(kou)停(ting)止線或(huo)(huo)人行(xing)橫道線以內，已經繼續(xu)通(tong)(tong)行(xing)；黃(huang)燈(deng)(deng)(deng)(deng)閃爍(shuo)時，警告車(che)輛注意安全。