专题限时训练(三十七)[科普知识型阅读理解(一)](限时:25分钟)(一)Trafficlightsarekeytoolsforregulatingtrafficnow
Theyarenot,however,perfect
Driversexchangethetrafficjamsthatwouldhappenatunmanagedcrossingsforapatternofstopgomovementthatcanstillbeannoying,andwhichburnsmorefuelthanasmoothpassagewould
Creatingsuchasmoothpassagemeansadjustingavehicle'sspeedsothatitalwaysarrivesatthelightswhentheyaregreen
Thatistheoreticallypossible,butpracticallyhard
Roadsidesignswiredtotrafficlightscanhelpgetthemessageacrossacouplehundredmetresfromacrossing,butsuchsignsareexpensive,andarenotwidespread
MargaretMartonosiandEmmanouilKoukoumidisatPrincetonUniversity,andLiShiuanPehattheMassachusettsInstituteofTechnology,however,haveanideathatcouldmaketheprocesscheaperandmoreeffective
Insteadofahardwirednetworkofsigns,theyproposetousemobi