Study On The Cloud Model Of Operating Speed Based On Road Alignment And Sight Distant

Traffic safety has been the international study hotpot and direction. In the past, researchers often thought that traffic accidents were caused by vehicle mechanical problems and drivers'mistake. After many years research, researchers have found that road geometry alignment has an important reason of traffic accidents, which is not only the infrastructure of transportation, but also the basic condition of vehicle traveling.As the skeleton of road, road geometry alignment design of horizontal, vertical section and cross-section and geometry alignment combination are permanent. The irrational road geometry alignment designs and inconsequent geometry alignment combinations may evoke traffic accidents. We should evaluate the quality of road geometry designing in stage of road designing to avoid designing unreasonable road geometry alignments and geometry alignment combinations.The model of operating speed is important in the design of road geometry alignment and the evaluation of the quality of road geometry designing. The study of operating speed model in our country started late. As yet, Ministry of Transportation hasn't put out our country's operating speed models universally applied in designing road. And existing operating speed models are about the relationships between operating speed and a certain road alignment, which are based on statistics. The operating speed in these models is certain. But, the operating speed from different drivers driving different vehicles on the same road section is uncertain. Even if the same driver driving the same vehicle on the same road section at different times, the operating speed is uncertain. That is to say, the operating speed from traditional operating speed models is certain. These models can't reflect the true characteristics of operating speed. In order to reveal the authenticity of operating speed, we use the cloud theory setting up the cloud model of operating speed based on radius of horizontal curve, longitudinal grades and sight distant in this paper, whose operating speed is uncertain. Learned from the international advanced theories of artificial intelligence with uncertainty and the existing operating speed models, based on the cloud model, the operating speed model including radius of horizontal curve, longitudinal grade, sight distant. And the following works have been done mainly.1. Developed a S3 radar speed software. As there is some bug in STALER S3 Doppler radar speed software from manufacturer, depending on streaming speed data protocols, I have programmed the S3 radar speed software by myself. Used different angles between the axis of the S3 center line and vehicle driving central line, measured operating speed at accelerating decelerating and cruise cycles. Compared the operating speed with operating speed from Driftbox, come to the conclusion that the angle is limited below 15°while measuring speed.2. Constructing the operating speed experiment. Radius of horizontal curve is calculated by longitude and latitude which are measured by Driftbox. Considering the traveling track of vehicle from different driving styles is not consistent with road alignment, we choose radius of horizontal curve from design handbook; longitudinal grade is calculated by height measured by Water Level; sight distant is measured by laser range finder; operating speed is measured by radar speed sensor and Driftbox. We have spent a week experimenting on Antu-Erdaobaihe secondary highway at mountain area in Jilin Province.3. Establishing operating speed database. The database is set up in 1m sampling interval containing mileage, latitude, longitude, curvature, longitudinal grade, sight distant, superelevation, vehicle type, sampling time, operating speed, sampling tool, driving direction, yaw rate and so on. Then analyzed the impact of radius of horizontal curve, longitudinal grade and sight distant of operating speed by experimental data form road sections K27+100-K27+400 and road sections K77+400-K77+800. The conclusion is that radius of horizontal curve, longitudinal grade and sight distant all affect operating speed.4. Studied on cloudtransform algorithm of operating speed and road alignment. Using cloudtransform theory put forward by academician Li Deyi, mining concepts automatically from data in operating speed, radius of horizontal curve, longitudinal grade and sight distant. These concepts will be input in the cloud model of operating speed. 5. Studied on cloud reasoning algorithm of operating speed. The cloud reasoning of operating speed based on three dimensional cloud models is studied. Maximum discriminance is applied in antecedent cloud generator. Rules base in the operating speed model is created by rules from fuzzy neural logic system from MATLAB tools automatically and original data. Consequent cloud generator structures virtual cloud from cloud drops. The Expectation of virtual cloud will be output as operating speed.6. Validated the cloud model of operating speed through experimental data forward and reverse on road section K27+100-K27+400. The conclusion is that operating speed from the model set up in this paper reflects the true characteristics of operating speed. Operating speed from cloud model is consistent with operating speed from trials on circular curve and straight line segment before circular curve.