《城市道路交通规划设计规范》的回顾与思考——兼论交通组织在路网规划中的重要性

《城市道路交通规划设计规范》(GB50220-95)实施已逾20年。对其回顾与思考,旨在深刻认识交通、路网规划规范、规范执行之间的关系,促进交通、路网规划问题的破解和规范的完善。95版规范提出了3项关键要求:(1)城市道路网的形式和布局要依据土地使用、客货交通源和集散点的分布、交通流量流向等因地制宜予以确定;(2)各等级道路的路网密度指标要求;(3)支路满足公交通行、支路网密度伴随容积率增加而加大的要求。相关研究和路网案例表明这3项要求具有先见性和科学性。其核心思想是倡导合理的交通结构、路网结构和交通-用地的相互协调。要求(1)强调结合交通需求的路网交通组织的重要性,要求(1)是实现要求(2)、(3)的前提与方法。良好的路网是合理交通组织的结果,合理交通组织是有效满足以人为本的交通需求的结果。难以驾驭复杂情况下的路网交通组织、选择性地执行规范的建议或控制指标、放弃或忽视95版规范的核心要求,是导致中国城市路网规划问题的关键原因之一。

REVIEW AND THINKING ON CODE FOR TRANSPORT PLANNING ON URBAN ROAD: IMPORTANCE OF TRAFFIC ORGANIZATION IN ROAD NETWORK PLANNING

The Code for Transport Planning on Urban Road (GB 50220-95) has been implemented for more than 20 years.The purpose of this paper is to deeply understand the relationship between traffic,road network planning code,and code implementation through a review and reflection to the code,in order to tackle the problems in traffic and road network planning and to further improve the code.The 95 version of the Code proposed three key requirements:① the form and layout of urban road network should be determined according to local conditions of land use,the distribution of passenger and freight traffic sources and distribution points,traffic flow directions,etc.;② the requirement on density index for every grade of urban roads;③ the requirement that branch road should support bus public traffic,and the density of branch road network should be increased along with the floor area ratio.Relevant research and road network cases show that these three requirements are insightful and scientific.Its core idea is to promote a reasonable traffic structure,road network structure,and the coordination between traffic and land.Requirement 1 emphasizes the importance of the road network that is combined with the traffic demand that is the precondition and method for realizing requirements 2 and 3.A finely designed road network is the result of reasonable traffic organization;and reasonable traffic organization is the result of effective fulfilling of people-oriented traffic demand.One of the key reasons leading to the problem in China's urban road network planning is the incompetence in managing complicated traffic organization of road network,the selective implementation of the normative suggestions or control indicators in the Code,and the abundance or ignorance of the core requirements of the 95 version of the Code.