低碳补贴下的武汉市居民出行方式选择边际效应

Marginal effect of Wuhan residents ’travel mode under low carbon subsidy scenario

为促进居民选择更低碳的出行方式,以武汉市主城区居民为研究对象,定义并设定低碳补贴情景,以SP(Stated Preference)调查数据为基础,将性别、年龄、职业、补贴占收入比、出行距离选为自变量,分别建立考虑低碳补贴前后武汉市居民常用的出行方式,综合调查所得的数据,运用随机效用模型,选择多项logit(Multinomial Logit)模型建立居民出行方式,比较2个模型分析自变量是否改变,再计算自变量对因变量的边际效应,分析碳补贴情景下各自变量对居民出行方式选择的影响。结果表明,在低碳补贴情景下,居民选择小汽车出行的概率受出行距离增长的影响较小,边际效应仅为0. 01;低碳补贴对居民选择公共交通、减少小汽车出行有促进作用;年轻群体和低收入群体更愿意选择公共交通等低碳出行方式,高收入群体则相反。由此,根据不同群体居民的出行方式特性,政策制定上建议对年轻群体和低收入的高年龄群体加大优惠力度,同时将补贴直接发放到个人,增强补贴效果,以针对性诱导居民低碳出行,进一步减少道路交通出行的碳排放。

To promote the residents to choose a lower-emission travel mode,we researched on citizens living in the main urban areas of Wuhan and define and seta low carbon subsidy scenario by conducting a SP (Stated Preference) survey with 1 600 questionnaires. And,for the said purpose,we have chosen samples of proper gender,age,occupation,subsidy to income ratio and travel distance as the independent variables. And,specifically,we have also merged some uncommon travel choices,such as taxi and electric bicycle,for we are trying to dive into the residents’ common travel modes. As a result,we have divided the choice of travel modes into the following 5 subclasses: that is,railway,bus or tram,private car,bicycle and bare-foot walking. Then we have made a study of the features of the travel modes of Wuhan residents by comparing the 2 multinomial logistic models before and after the low-carbon subsidy,respectively. As is shown in the paper,the independent variables have changed,which suggests that the low carbon subsidy has impact on the travel choice.Specifically,we try to work out the marginal effects of the independent variables through the analysis under the carbon subsidy scenario. The results of our analysis indicate that under the lowcarbon subsidy scenario, (1) The probability of the car travel is less affected by the increase in the travel distance,and the marginal effect can only be 0. 01;(2) The low-carbon subsidy has a positive impact on the residents’ choice for the public transportation means and a negative impactonthe car travel;(3) Young groups and low-income groups may prefer to choose the low-emission travel modes,such as railway and bus or tram,whereas the higher-income groups might go on the contrary. In the paper,we have also analyzed the characteristic features of the travel modes of different groups of residents. And,last of all,we suggest that the relevant departments should formulate and create suitable policies to propose preferential alternatives for the young groups and low-income and old-age or senior groups. And,simultaneously,we prefer that subsidy has to be directly given to the individuals so as to enhance the effect of subsidy particularly to the people in real needs to choose the lower-emission travel modes,so as to reduce the carbon emission of the on-road traffic.