Bridges provide vital links in the road network. Bridges are one of the network elements that require the most attention because the investment in bridges represents approximately thirty percent of the total investment.

Road users, road owners and other interested parties - in the following referred to as society - are currently setting up new socio-economic (S-E) demands on the road network including bridges e.g. demands for increasing passability or a reduction of the impact on the environment.

These guidelines deal with the possibilities of implementing modifications of bridges or strategies to meet current and future socio-economic demands on new and existing bridges.

Future demands apply to bridges under construction and existing bridges under operation, maintenance and repair, etc. Present S-E demands are only applied to existing bridges. Present demands on new bridges - the present design standard - are not discussed.