Beijingisplanningtobuildtheworld'sbiggestsubwayanddramaticallyexpanditsbusnetworkaspartofeffortstocombatthecity'sfast-increasingtrafficgrid-lock,statepresshassaid.TheChinesecapitalwillexpanditssubwaysystemto273kilometers(169miles)by2010andto561kilometersby2020,surpassingLondonasthecitywiththeworld'smostextensiveunderground,thereportssaid.Thecity'scurrentmetrorailsystemis115kilometers,with54kilometersofsubway.Thecity'snewlyapprovedfive-yearpublictransportplanwillshiftthefocusfrombuildingroadsforcarusetoconstructingahigh-speedpublictransportsystemtoeasethegrowinggrid-lock."WhenBeijingcitizensareinthecitycenter,wewantthemtobeabletogettoplacesfasterbyusingpublictransportthanbyusingacar,"thereportquotedLiuXiaoming,viceheadofthecity'strafficdepartment,assaying.Headdedthatbesidescompletingfivenewraillinesby2010,includinganalreadyannouncedlightrailconnectingthecitycentertotheairport,Beijingwillalsobuild300kilometersofspecializedbuslanes.By2010,itishopedthat40percentormoreofthecity'sdailycommutingwillbedoneonpublictransport,withuptosixmillionpassengerscommutingbyrailandover13milliontravellingbybusdaily.AlthoughBeijingcurrentlyonlyboaststwosubwaylinesandtwolightrailtracks,threemoreundergroundlinesareunderconstructionandslatedtobecompletedby2008whenthecityhoststheOlympicGames.