Freeway Ramp Design, 3d Modeling And Application

In recent years, road traffic driving simulation system is a hot international development and application. Its advantage is to provide people with a virtual environment on the roads to study the different relations between drivers and road, transport, environment, then achieve the aim of optimizing the design of road.The development of virtual reality and computer simulation technology offers a technological guarantee for researching and developing driving simulator. Utilizing driving simulator to process expressway traffic simulation, which must offer the virtual driving environment for driver at first, and then can enable the driver to get true driving feel during the process of handling the automobile. So the visual modeling is most important to the road transportation simulation.The visual modeling system that our laboratory researched and developed independently can do the model of slope, reintainiing walls, tunnel, bridge, topography, etc. And has completed the parametric design of the transport infrastructure and scenery model such as street lighting, median divider, guardrail, ditch, traffic sign, tree, etc. But highway entrance and exit ramp has not had a unified modeling technology. In order to solve this problem. I have designed a special ramp modeling software using parametric method to export visualization data of ramp model. This paper details the modeling algorithms and programming method of the single circular right turn ramp, the basic right and left turn ramp, turn left loop ramp.Our laboratory has established abundant scenes of the current road traffic. Some modeling scene can be used repeatly (for example: tunnels, bridges, entrance and exit ramp as well as long straight sections scene). If we are able to draw on the old scenes to design new scene, the repetitive modeling work can be reduced, and greatly improving the efficiency of visualization scene data's export. Hence, it is necessary to design a modular modeling software, it can draw on some of the old scenes to build new scene with translation, rotation, zoom method. This paper has described in detail the core of the software, the ideas and algorithms of translation and rotation, and at last, showed some design outcomes and application examples.In addition, this paper has presented a method to determine the length of speed change lane. In order to compare the rationality of the different length of the speed change lane. I have designed two virtual scene of the An Feng-ying's speed change lane. One based on the actural length, the other one decided by operating speed. Then used experimentation to analyse which length is more reasonable. The result showed that the length of the speed change lane decided by the operating speed is scientific and the the length of the actual speed change lane is too short.Ramp modeling and three-dimensional view modular modeling software's demonstration results showed that it can not only improve the efficiency of the data generated. But also meet the need of the fidelity and real-time. These softwares have been used in traffic simulation experiments of some highway of YunNan province and lay a good foundation for future's road geometric alignment design, the research of the impact of driver's behavior and visual range to the safety's evaluation.