PREDICTING TRAFFIC SIGNS FUNCTIONAL SERVICE LIFE USING SURVIVAL ANALYSIS METHOD

In order to fulfil their function, traffic signs must be visible to all traffic participants in all weather and traffic conditions. This is especially important in conditions of reduced visibility in which, due to the limited amount of visual information, signs present basic elements for informing traffic participants about the upcoming road condition. The quality and timeliness of the informations transfer, in mentioned conditions, are directly related to the retroreflective characteristics of traffic signs. If the signs do not meet the minimum prescribed values of the retroreflection, the authorities should replace them. Given the amount of traffic signs on the roads, the type of retroreflective material and their age, the substitution of signs that do not meet the prescribed values requires significant financial resources. The purpose of this paper is to predict, using Survival analysis method, when the traffic signs, from the aspect of retroreflection, become dysfunctional, i.e. when their replacement is required. The results of this paper may help the road authorities in planning periodic measurements of traffic signs retroreflection and ultimately optimizing the traffic signs maintenance activities, all with the goal of increasing the overall road safety.