The maintenance cost of bridges is huge in every country e. g. in the USA it is (approx.) 41.8 G$. This causes a 6.2 % GHG emission rise annually. Reducing and minimizing cost, GHG level and CO2 pollution is a key factor and a major goal for sustainability. This study presents a comparative life cycle assessment (LCA) of bridges with different support systems and construction technologies but with the same span and location. LCA considers regular and irregular bridge maintenance as well having a great influence on the need and timing for major maintenance or restoration in every 25 to 30 y. Regular maintenance means every 1 - 5 and 10 - y minor maintenance works take place. The analysis is based on primary data collected in Hungary examining fully constructed bridges. For the LCA, the cost of maintenance over a 100 y timespan is based on NIF regulations, the total rate of CO2 pollution and the EF (Ecological Footprint, Gha) level is used (Long et al., 2020;). In practice the maintenance of the bridges take place occasionally when the damage on the bridges are already visible and cannot be postponed based on the in - depth interviews with experts. It is assumed that the cost, EF and CO2 pollution of the regular maintenance over the examined timespan is less compared to results of the irregular life cycle model. Based on the case study presented, it can be concluded that the cost of LCA for regular bridge maintenance is 637,348.32 (k€) and for irregular bridge maintenance it is 994,415.12 (k€). The CO2 pollution for regular bridge maintenance is 12,948.24 (kt) and for irregular bridge maintenance is 13,876.86 (kt). The EF pollution for regular bridge maintenance is 3,237.06 (kGha) and for irregular bridge maintenance it is 3,469.22 (kGha). Considering the long - term sustainability aspects, it is recommended that the maintenance should be a regular and a controlled activity. It is vital to draw the attention of the decision makers, the legislators of the businesses, the maintenance operators, and the inspectors to these sustainability aspects.