Thefirstcauseisthegreatincreaseinthenumberofprivatecars.Carstakeupmorespacebuttheycarryfewerpeople.Someprivatecardrivers，ignoring(忽视)trafficregulations，driveonlyforthesakeoftheirownconvenience，blockingthewayofotherpublictransportationvehicles.Thesecondcauseistheslowandinefficientconstructionandimprovementoftheroadsandstreets.Withalargepopulationandnumbersofautomobilesincreasing，someroadsstillremainunimproved，whichwillsurelyleadtoproblems.
Thelastcauseistheinsufficient(不足够的)managementofthetrafficsystemandthepeopleslackofawarenessoftrafficrules.Manypedestrians(行人)crossthestreetsevenwhenthetrafficlightsareagainstthem，whichisanobstacle(障碍物)totheflowoftraffic.Thenhowtosolvethisproblem？Somesuggestlayingdownmoreroadstomakethetrafficlesscrowdedandspeeduptheflowoftraffic.Othersbelievethatweshouldopenupmorepublicbusroutes，sothatmorepeoplewilltakethepublicbusesinsteadoftravellingbycarandbicycle.
Thoughtheabovetwoviewssoundreasonable，theyhavetheirowndrawbacks(缺陷)．Theformermaytakeupmuchlandwhichcouldbeusedforfarmsandhouses.Thelattermaycauseinconvenienceforthosewhoareusedtotravellingbycarorbicycle.Ithinkthebestanswertothetrafficproblemisacombinationofthetwo.Moreroadscanbebuilttoholdmoretrafficandmeanwhilemorepublicbusroutescanbeopeneduptothosewhoprefertousethepublictransportation.