可持续城市机动性规划与一般常规性的城市交通规划是有区别的。机动性(mobility)和可达性(accessibility)是一对有关出行方式(mode)和出行场所(site)的相对而又互补的概念。二者在数理上没有标准的定义,但从基本概念上来说,机动性是对出行方式的时间便捷性的度量,而可达性是对出行场所的空间便捷性的度量。就某种出行方式而言,机动性越高,则针对特定出行场所的可达性可能很低,反之亦然。例如 There is a difference between a sustainable urban mobility plan and a typical, regular urban transport plan. Mobility and accessibility are a pair of relative and complementary concepts about mode of travel and site. Both have no standard definition in terms of math, but from the basic concept, mobility is a measure of the time convenience of the mode of travel, and accessibility is a measure of the spatial convenience of the place of travel. In some modes of travel, mobility is higher, accessibility to particular places of travel may be lower, and vice versa. E.g