中文摘要：

以中原经济区为研究区域，采用网络分析和栅格分析相结合的方法，运用加权平均旅行时间、相对可达性和区域平均可达性指标在对各县市可达性及改善状况进行比较分析的基础上，对区域可达性空间格局及演化特征进行探讨。结果显示：各县市可达性均获得了较大的提升，但县市可达性在不同地区和不同时期还存在较大差距：区域平均可达性呈现出以中原城市群为核心向外围地区递减的态势，可达性中心区的范围逐步拓展，交通干线指向性明显，平原地区可达性优于山区、丘陵或盆地；不同发展阶段的可达性变化幅度也不均匀，可达性水平较差的地区改善程度明显，高速公路建设有利于推动地区间可达性的均衡发展。

英文摘要：

Taking Central Plain Economic Region as a sdudy case, selecting weighted mean travel time and accessibility coefficient as indicators, the counties＇ accessibility level, relative accessibility and their variation are calculated by the network analysis, the evolution pattern of the counties＇ accessibility and accessibility variation are discussed. The spatial pattern and evolutionary characteristics of regional average accessibility are probed by the method of grid analysis. Following the construction of expressway, each county＇ s accessibility has gained a significant upgrade, but the disparity of counties＇ accessibility level is remarkable in different stages and among different regions. The spatial pattern of regional average accessibility level reduces gradually from Central Plain Urban Ag- glomeration to the periphery, the scope of superior accessibility area is expanding gradually, especially along the transportation corridors of primary expressway. In addition, the spatial difference is remarkable between plain and mountain areas. The accessibility variation is also disequilibrium in different stages and among different regions, the accessibility variation is more significant in periphery zones where the accessibility is poor, so it is proved that the construction of expressway network is propitious to the equally development of regional average accessibility.