Upgrading projects include works required to increase the capacity of the infrastructure, improve its quality and functionality, apply new technologies and also to adapt the infrastructure to climate change and increase its resilience to natural hazards. This type of projects may present specific situation in which only a change in a feature of a transport infrastructure under operation occurs. Using the above listed tools differs depending on the extent of upgrading. Some projects include only small adjustments in order to increase speed or a slight widening of existing infrastructure, while others are more extensive, such as replacing a two-lane road with a four-lane dual carriageway or a change from a single to a multi-track railway line.
Depending on the extent and nature of the upgrade, the processes which need to be applied, such as EIA or other, need to be determined. Appropriate tools are then chosen according to the necessary processes. Often, infrastructure to be upgraded was built at a time when requirements to reduce fauna mortality and fragmentation were not in place. In such cases, upgrading represents an opportunity to implement mitigation measures according to current standards following a strategy of maximizing the defragmentation. This is the most common reason for the addition of wildlife passages, fauna deterrents or warning systems on upgraded roads as well as measures to protect birds on powerlines, or other interventions.