Abstract:With the development of expressway construction,the number of running vehicles has increased,heavy traffic accidents are often caused by the local dense fog on the expressway.The monitoring and early warning work of the local dense fog on the expressway has not yet been carried out,in order to promote the implementation of the related standards of local dense fog classification and early warning and reduce traffic accidents.Based on the law of atmospheric attenuation, the results of video image analysis of luminous objects along the road, forward scatter visibility meter data verification are used,To explore the relationship between horizontal visibility and luminance parameters of luminous objects.The results showed that:(1) There is a significant correlation between visibility and luminance parameters of luminous objects in local dense fog weather.(2) There is a linear relationship between horizontal visibility and some parameters of luminance of luminous objects, and a linear regression model can be established.(3) Combined with the "Warning levels of expressway local dense fog" standard, the local dense fog weather can be classified early warning.(4) The video monitoring and early warning platform can be used to release the classification warning information to the traffic operation, management department and traffic participants.(5) The video of luminous objects image monitoring and early warning method for the local dense fog is scientific, innovative and feasible, which can realize continuous monitoring and early warning.The combination of video analysis of luminous objects, GIS and GMS navigation will form a timely and accurate local dense fog classification early warning system for expressway.Early Warning model for video image monitoring and will become one of the main means for the local dense fog monitoring and early warning of expressway.