The main modes of transport in Bulgaria in terms of infrastructure and services are road and rail, followed by water and air. Road transport is the most important mode, generating over 95% of traffic, while rail transport is responsible for about 3.5% of the number of trips in the country.

The most significant previous impacts on infrastructure from weather events in Bulgaria have resulted from floods and landslides. The most vulnerable are the national road network and municipal transport infrastructure (streets, roads and public urban transport infrastructure).

In the medium and long term, the main risks for the Bulgarian transport system expected as a result of the projected climate changes are:

- Flooding: the frequency and impact of flooding is expected to increase under all climate change scenarios. Floods cause significant damage to road and rail infrastructure by damaging the sub-base layers of road or rail structures. Water can undermine foundations, which can cause catastrophic damage to engineering structures

- Landslides: rainfall is a major contributor to landslides and although total annual average rainfall is expected to decrease, landslides will continue to be a serious problem due to the expected higher frequency of extreme rainfall events. Landslides cause serious damage to road and rail infrastructure and to river banks. They may cause long-term disruption of operations and/or restricted access for certain population groups and in certain economic areas to certain settlements and/or economic areas

- Blizzards and snowfall: In the long term, the annual volume of snowfall is expected to decrease, but in the short to medium term blizzards and heavy snowfall will continue to be a major source of disruption to services on all modes of transport. Northern and north-eastern parts of the country are particularly susceptible to winter disruption due to high winds and snowfall

- Extreme heat: It damages asphalt-concrete roads by softening the binding component, bitumen. This reduces the load-bearing capacity of the pavement and, in combination with the stresses of vehicular traffic, leads to deformation and rutting, increasing the risk of accidents. In addition, the combination of high temperature and strong sunshine causes surface cracks and shortens the life of road surfaces. As far as railway infrastructure is concerned, extreme temperatures can cause bending of the rails, which in turn leads to the need to reduce the maximum permissible speed or even interrupt traffic