This paper reviews several extrapolation methods (for example fitting a distribution to the upper tail of the data and Rice's formula) implemented in the background study of the normal load model, LM1, in Eurocode 1, Part 2. Recent extensively used extreme value theory (EVT) based methods (block maxima method and peaks over threshold method) in other domains such as meteorology (for flood levels, quantity of rain, etc) are also reviewed. The methods are applied on weigh-in-motion (WIM) data to extrapolate characteristic values of long return period. Two different types of comparisons are made on extrapolating extreme gross vehicle weight (GVW), the total load on lane (TLL) and the induced traffic load effect (TLE). The first focuses on differences between the various prediction methods, and the other on changes between past and recently recorded data in France. The results show that the EVT based method is the better one for extrapolation. Extrapolation (prediction) method, gross vehicle weight, total load on lane, traffic load effect, characteristic value