城市公交价格组合策略的系统动力学建模与仿真

106201012JournalofTransportationSystemsEngineeringandInformationTechnologyVol10No6December2010:10096744(2010)06012107孙广林,王健*,胡晓伟(,150090):城市公交价格系统是由公交出行者运营者管理者三个主体构成的多变量多反馈非线性的复杂系统,不同价格组合策略对利益主体的影响不同.由公交主体在系统中的作用将公交价格系统分为公交供给子系统公交企业收益子系统公交需求子系统三个子系统.采用系统动力学方法,建立了城市公交价格系统变量间的因果关系图和流图,以及公交价格系统动力学模型.通过提高或降低公交补贴标准公交车辆供给公交服务价格三个指标值,形成不同公交价格组合策略方案.在高低两种经济发展水平背景下,以哈尔滨市公交企业为对象分五种情境对公交价格组合策略方案进行仿真,得出政府补贴公交企业利润,以及乘车等待时间的变化趋势.选择社会福利和资金利用比指标,评价不同公交价格组合策略实施的效果.公交价格组合策略分析,为城市公交价格政策的制定和实施提供了参考依据.:城市交通;城市公交;价格策略;系统动力学;社会福利:U491:ASystemDynamicsModelandSimulationofIntegratedPriceStrategiesofUrbanPublicTransportSUNGuanglin,WANGJian,HUXiaowei(SchoolofTransportationScienceandEngineering,HarbinInstituteofTechnology,Harbin150090,China)Abstract:Thepricesystemofurbanpublictransportiscomposedoftravelers,operatorsandmanagers,whichtobeseveralnonlinearfeedbackloopswithmultiplevariables.Eachintegratedpricestrategyhasdifferentinfluencetodifferentbody.Thepublicpricesystemisclassifiedintothreesubsystemsbythreebodies:supplying,payof,fdemandsubsystem.Thispaperusessystemdynamicstodevelopcausalitygraph,flowgraph,andmodelofpublicpricesystembasedonvariables.Theintegratedstrategiesarethevariationsincludingincreaseordeclineamongsubsidyfromgovernment,newbusownedbyoperatorsandpriceofpublic.PriceschemeissimulatedbyfivesituationsunderhighandlowlevelofeconomicinHarbin.Theresultsshowthechangingofthesubsidies,theprofit,andwaitingtimewithinpredictedperiod.Selectingsocialwelfareandtheratiooffundsusagearetoevaluatetheinfluenceofdifferentlyintegratedpricestrategies.Theresearchesintointegratedpricestrategieshavekeymeaningtomakeandimplementpoliciesofurbanpublictransport.Keywords:urbantraffic;urbanpublictransport;pricepolicy;systemdynamic;socialwelfareCLCnumber:U491Documentcode:A:20100525:20100918:20101029:(71073035).:(1981-),,,.*:[e-mail]1.2090,[1,2].2008,,.,.,MarshallBanister,(500),[3].Abrate,69[4].,Matas(),7%[5].,1969Forrester[6].,,,[7].,,[8].,,,[9].,(),,,.22.1,,.,,()(),..,()()!!!.2.2()(),.1.1Fig.1Structurerelationshipforpublictransportpricesystem,.1750,8000,54,3,1480km.20077,0.9,0.5,1;!!!.,1,2.1222010122Fig.2Causalityforpublictransportpricesystem2.(1)∀:++++++-+.∀,;,,,,,.(2)#:++++-.#,,,,.,,,,,.33.12050MITJ.W.Forrester,[10].1.1Table1ThevariablesofpublictransportpricesystemPotentia&ldemand0people/weekSupply100vehicle/weekrea&ldemand!people/weekdemand!people/weeklos!hourcorporate&profit!yuanwai&ttime!hourerror!hoursubsidy&amount!yuanoperate&cost!yuan/weekcorporate&payoff!yuanservice&frequency!/hourvariable&cost!yuan/weekprice1yuansubsidy&min8000yuan/yearsubsidy&rate6∃!time&value50yuan/hourfixed&cost2000yuan/weekpurchase&coefficient5∃!fue&lprice6yuan/Ldistance25kmconsumption0.3L/kmdesire&los5!operate&time12hourattrac&trate!people/yuan/weeknew&bus!vehicle/weekdepreciation!vehicle/week,1,.,.,,los=a/[price+(wai&ttime%time&value)b](1)a,b.,[11]wai&ttime=1/(service&frequency%2)(2)1231063.2,()(),Vensim_PLE,3.3Fig.3Theflowofpublictransportpricesystem3.3Vensim_PLE,:(1)(LevelModels).,,.L1L2:L1Potentia&ldemand.K=Potentia&ldemand.J+DT%attrac&trateL2Supply.K=Supply.J+DT%(new&bus-depreciation)(2)(RateModel).,R1R2.,R3.R1attrac&trate.KL=TABLE(Tattrac&trate,error,-4,4,1)Tattrac&trate=800/700/600/500/400/300/250/200/150R2new&bus.KL=IFTHENELSE(corporate&profit&0,0,corporate&profit%purchase&coefficient/200)R3depreciation.KL=0.08+STEP(0.02,50)(3)(AuxiliaryModels).,(1)a,b602;5,12,A4;84,A5.A1corporate&payoff.K=demand.K%priceA2subsidy&amount.K=subsidy&min.K+RAMP(subsidy&min%subsidy&rate,0,100)A3corporate&profit.K=corporate&payoff.K+subsidy&amount.K-operate&cost.K124201012A4service&frequency.K=Supply.K%5/12A5variable&cost.K=service&frequency.K%distance%consumption%fue&price%84A6operate&cost.K=service&frequency.K%variable&cost.K+fixed&cost.KA7wai&ttime.K=1/(service&frequency.K%2)A8los.K=60/[price+(wai&ttime.K%time&value)2]A9error.K=desir&los-los.K(4)(TableFunctions).A1T1.A1rea&ldemand.K=TABLE(Trea&ldemand,price,0.4,1.5,0.1)T1Trea&ldemand=330000/328000/326000/324000/323000/322000/322000/321000/320000/318000//315000/313000(attrac&trate)R1.(5)N.N1.44.1(1).2007,1,.(2).,,2007,2.2Table2Theresultsofvalidation()3135003058202.4%()1001044%2,5%,.,.4.23100,25km;100,1,2007;,,,;;:,.,.3.3Table3Theschemeofintegratedstrategiesofpublictransport(%)1.01001.00.81101.50.51205.01.21000.81.41000.64.3(1)(subsidy).(subsidyn,n=1,2,∋,5)4.,,subsidy5subsidy4subsidy1subsidy2subsidy3.,,;,,,.(2)(profit).(profitn,n=1,2,∋,5)5.,(profit3profit2profit1profit4profit5),.,,.,,.1251064Fig.4Thesimulationresultsofsubsidyunderhigherandlowereconomic5Fig.5Thesimulationresultsofprofitunderhigherandlowereconomiclevel(3)(wai&ttime).6.,,.,,,,,;,,,,.6Fig.6Thesimulationresultsofwaitingtimeofpassengersunderhigherandlowereconomiclevel4.4.,,(),:SW=corperate&profit+PU(3)SW;PU,.PU=demand%error(4)error=desire&los-los(5)EUF,:EUF=subsidy&amount/SW(6)(3)~(6),(126201012),4.4Table4Theestimationofintegratedstrategiesofpublictransport()1.70E+070.07117.7E+070.00869.9E+070.0047.70E+070.01511.8E+070.009,:(1),;,,.(2),,;,.5,,,.,:,(),,,;,