Foremost the thesis put forward one important index, town accessibility, and analyzes mechanisms among accessibility, roads and towns. So accessibility model can support optimization of regional town roads system.

• 并提出影响小城镇交通优化目标的重要指标一可达性，在可达性模型的支撑下，实现区域可达性与交通、城镇之间的机制分析，从而为以可达性为目标的区域城镇交通系统优化提供支持。