Freeway Traffic Safety Evaluation Method Based On Multi-source Heterogeneous Data

The rapid construction and development of freeway in China have promotedthe economic growth and social development, but also have consumed a lot ofnature resources and energy, caused traffic safety accident-prone, and had a hugeimpact on the people life and wealth, as well as the environment. With the estab-lishment of a healthy, harmonious, and sustainable development society, freewaytraffic safety has been paid more attention from managers and researchers.On the basis of multi-source heterogeneous traffic safety data, through datafusion and data mining to analyze the key factors affecting the level of safety,and develop a reasonable, reliable traffic management and control strategies toreduce the traffic accident casualties and economic losses, aiming to get the besttransportation efficiency, has become a cutting-edge topics in freeway trafficsafety researches. This thesis followed the technical route of regional freewaynetwork “multi-source heterogeneous data fusion, accident risk judgement, inte-grated assessment of safety rating, traffic safety performance evaluation, caseapplication”, based on multi-source heterogeneous data fusion to explore freewaytraffic safety performance evaluation.Firstly, the sources of regional freeway network traffic safety multi-sourceheterogeneous data were analyzed, including accident data and environmentaldata. Based on data fusion theory, three fusion structures of the freeway trafficsafety data were put forward, including the series, parallel and mixed fusionstructure. Then presented the freeway traffic safety data fusion system functionstructure, and established multi-dimensional association rules Apriori algorithmprocesses, and gave the description of the algorithm, which can achieve the indi-cation of freeway traffic safety evaluation elements, such as the accident-pronepoints, road level and road network level.Secondly with the combination of the support vector machine and decisiontree method, this chapter constructed the freeway traffic safety risk judgementtechnology through the traffic flow parameters. In order to analyze the relation-ship of traffic accidents and the conditions of traffic flow based on support vectormachine algorithm to establish the freeway traffic accident risk prediction model.Considering the relationship between the SVM classifier and variable feature se-lection method, to filter out the impact of traffic accidents occurred the salient features of variables. Based on the corresponding optimal feature variables andkernel function parameters to build the SVM predictor, and compared the vari-able selection process on the accident risk prediction results.Thirdly, based on multi-source heterogeneous data fusion, this chapter ex-plored the impact of inclement weather and inclement weather. Then proposedregional freeway network traffic safety situation assessment model under inclem-ent weather, especially the safely operation vehicle speed under different visibil-ity and precipitation conditions. And established the freeway traffic safety inte-grated assessment model to analyze the traffic safety under free flow state andcar-following state, a numerical example was proposed to verify the model.Then, referred to the SPFs （Safety Performance Functions） used by theU.S. Department of Transportation, to describe and predict the regional freewaynetwork traffic safety. This chapter established complied with the development ofChina’s regional freeway traffic safety performance function model, and pre-sented freeway traffic safety level method. And proposed regional freeway net-work traffic safety performance evaluation model based on fuzzy interval theory,which integrated the accident-prone points, freeways and road network traffic ac-cidents together, and from the "point-line-surface" level to combine the multi-source traffic data. Then this chapter applied this model in Zhejiang Provincefreeway network to analyze traffic safety situation.Finally, this paper took Jiangsu province freeway network as an example,analyzed the application of Jiangsu road network traffic safety situation assess-ment system. As well as predicted Jiangsu freeway rear-end accident risk, as-sessed the level of freeway traffic safety in Jiangsu Province, the traffic safetyperformance evaluation of Jiangsu Province freeway network, and according tothe evaluation result, this paper presented some recommendations for the im-provement of regional freeway network traffic safety.