In the 1990s, during the background works of Eurocode 1991-2 (Traffic loads on bridges), extreme loads and extreme load effects have been evaluated by using weigh-in-motion (WIM) data recorded at various European locations. The most used data file is a WIM data record, 2-week long, recorded at Auxerre on a French heavy trafficked motorway in 1986. Today, WIM records are longer and much more accurate due to the fast progresses of the WIM technology. Thus, they give a better account of the traffic variations over time. After the action COST323, self-calibration of WIM system has been generalized and the sensor and software technologies have been improved. Therefore, uncertainties in the calculation of traffic effects on bridges are lesser than 25 years ago. To update the maximum load effects calculated in the late 1980s and used for the calibration of the load model LM1 of the Eurocode 1991-2, using not only the most recent WIM data but also advanced extrapolation methods, extrapolations have been made using various methods (Gaussian fitting, Gumbel fitting, Rice formula, Generalized Extreme Value, etc.). Among the several extrapolation methods found in the literature, a choice has been made according to the objectives and the chosen methods have been applied to traffic loads and traffic load effects. Results are discussed with respect to the method robustness versus the traffic data, the period of extrapolation and the load effect considered so as to assess the likelihood of the final results.