TOD中“T”与“D”因素对小汽车出行距离的减量影响

国内以公共交通为导向的开发（transit-oriented development，TOD）研究大多集中在规划实践领域，对于TOD能在多大程度上降低城市居民小汽车出行距离依然有待明确。基于南京市城市居民出行调查数据，采用家庭所在地800 m范围内有无地铁站点定义TOD中“T”因素，以综合密度、混合度、步行评分作为“D”因素。在控制个人社会经济属性和家庭所在地位置因素的基础上，建立Tobit模型，研究TOD对居民小汽车出行距离的减量影响。通过划分TOD、only-T、only-D、non-TOD等4类家庭居住地，分析边际效应发现，当“T”因素从无地铁站点变为有地铁站点时，小汽车出行距离降低19.6%；“D”因素每增加0.01，小汽车出行距离平均下降0.7%；当“T”与“D”因素综合作用时，小汽车出行距离下降43.4%。依据上述研究结论，提出从only-T向TOD、从non-TOD向only-D转变的规划建议。

The effects of "T" and "D" factors of TOD on reducing the car kilometers traveled

Most of the studies on transit-oriented development TOD in China were focused on planning practice, and to what extent TOD can reduce the urban residents' car kilometers traveled was unclear. Based on the Nanjing household travel survey data, the "T" factor of TOD was defined by whether there was a subway station within the distance of 800 m from the household residence; the "D" factor of TOD was defined by residence density, mix, and walk score. After controlling for socioeconomic and home location factors, a Tobit model was proposed to study the effect of TOD on reducing the urban residents' car kilometers traveled. By classifying four residence types (i.e., TOD, only-T, only-D, and non-TOD) and analyzing the marginal effects, we found that the car kilometers traveled decreases by 19.6% when the "T" factor changes from no subway station to one subway station; and it decreased by 0.7% for every 0.01 increase in the "D" factor; the car kilometers traveled decreased by 43.4% if the effect of both "T" and "D" were combined. Based on the above findings, it was suggested that the planning studies should shift from only-T to TOD and from non-TOD to only-D.