The Interactive Feedback Research Between Road Network Capacity And The Floor Area Ratio In The Regulatory Plan

In the urban and rural planning system of our country, the comprehensive transportation planning was included in the stage of the urban master planning, and the traffic impact assessment for construction projects was in the stage of the site plan, it reflected the importance of transportation and land use coordinated development in the urban planning, but there did not have a clear traffic planning requirements in the regulatory plan, it cause the comprehensive transportation planning and the traffic impact assessment for construction projects could not be implemented, the traffic problems brought by the urban development is still grim. To coordinate the relationship between the transportation and land use, the traffic impact assessment for construction projects was gradually being valued by the city manager, it alleviated traffic congestion in a certain extent, but also appeared many problems. Firstly, faced with the regulatory plan which had a legal status the feedback effect to land use intensity of the traffic impact evaluation was limited because the traffic impact assessment for construction projects was in the level of the site plan. Secondly, as the Principal of the traffic impact assessment for construction projects, the developers often forced the traffic impact assessment passed by hook or by crook, making the traffic impact assessment useless. Thirdly, the city traffic is perplexing, it is difficult to grasp the actual traffic impact from the global perspective for the traffic impact assessment of construction projects because it only implemented in the micro level.According to these problems, doing interactive feedback research between road network capacity and floor area ratio in regulatory plan as the countermeasures was proposed in this paper, the core content and the key technology of traditional transportation planning were introduced into the regulatory plan preparation process, it would balance the traffic supply and demand on the basis of land use planning and promoting land development intensity and road network capacity to accommodate.Through the characteristics study of the various traffic modes, the car which is most sensitive to network congestion was selected as the research object, and the quantitative relationship between road network capacity and floor area ratio was established by the car trip generation rate. According to the different background traffic flow, the regulatory plan preparation objects were divided into the new development area and the urban renewal area, and the research methods of the interactive feedback between road network capacity and floor area ratio were given based on the OD estimation method and the "four stages" method.For the new development area, the research idea was to feedback the maximum car traffic that the road network can carry to the different plots by using the OD estimation and the preliminary planning of land use, and the adjustment method of unreasonable floor area ratio was given, it provided the auxiliary basis for floor area ratio determining in regulatory plan. For the urban renewal area, its research idea was from the traffic impact assessment, the mainly thought was to carry out the traffic demand forecast based on the scheme of land use planning which has initially identified the block floor area ratio by using the "four stage " method, it put the car traffic generation back to the road network planning, and to determine whether the floor area ratio was reasonable through the network load level, the adjustment method of unreasonable floor area ratio was given too. In the two kinds of research methods, the former was a negative feedback process which was from the road network capacity to the floor area ratio, and the latter was a positive feedback process which was from the floor area ratio to the road network capacity, both the two were achieved the interactive feedback between road network capacity and floor area ratio in the adjustment process of unreasonable floor area ratio.Through the interactive feedback research between road network capacity and floor area ratio, the transportation planning technology was introduced into the regulatory plan preparation, achieving the effective control of land development intensity in the view of traffic supply and demand balance, it provided technical support for the floor area ratio determine. This research also promoted the smooth connection between the comprehensive transportation planning and the traffic impact assessment for construction projects, giving full play to the role of regulatory plan, finally it would realize the coordinated development of transportation and land use to effectively deal with the city traffic problems.