Abstract: This paper is based on the research of the road net structure forming by radiation and ring.Firstly, it elaborates the relations between city transit circular road and city development, transportation requirements, development of products and coordination of landscapes in a new turn of city construction.Secondly, it acquires the mathematical model about the relation between circular route's location and the transportation origin-destination.At last, it deals with the principle of the defining of reasonable radius.So it makes plan of the circular road guided by the transportation requirements and combines with the development of city, forming a graceful building space in the belt between urban district and suburbs.

Key words: transit ring road, planning theory, reasonable radius

摘要： 以"放射+环"的路网结构为研究的基础,阐述了在新一轮城市建设中,城市过境环路与城市发展、交通需求、物业开发和景观协调的相互关系;得到了环路线位与交通起讫点相互关系的数学模型;探讨了合理半径确定的原则;从而,使环路规划以交通需求为导向,与城市发展相结合,在市区和郊区的过渡带上形成优美的建筑规划空间.

关键词: 过境环路, 规划理论, 合理半径