Visual condition inspections remain paramount to assessing the current deterioration status of a
bridge and assigning remediation or maintenance tasks so as to ensure the ongoing serviceability of the
structure. However, in recent years, there has been an increasing backlog of maintenance activities. Existing
research reveals that this is attributable to the labour-intensive, subjective and disruptive nature of the current
bridge inspection method. Current processes ultimately require lane closures, traffic guidance schemes and
inspection equipment. This not only increases the whole-of-life costs of the bridge, but also increases the risk
to the travelling public as issues affecting the structural integrity may go unaddressed. As a tool for bridge
condition inspections, Unmanned Aerial Vehicles (UAVs) or, drones, offer considerable potential, allowing a
bridge to be visually assessed without the need for inspectors to walk across the deck or utilise under-bridge
inspection units. With current inspection processes placing additional strain on the existing bridge
maintenance resources, the technology has the potential to significantly reduce the overall inspection costs
and disruption caused to the travelling public. In addition to this, the use of automated aerial image capture
enables engineers to better understand a situation through the 3D spatial context offered by UAV systems.
However, the use of UAV for bridge inspection involves a number of critical issues to be resolved, including
stability and accuracy of control, and safety to people. SLAM (Simultaneous Localisation and Mapping) is a
technique that could be used by a UAV to build a map of the bridge underneath, while simultaneously
determining its location on the constructed map. While there are considerable economic and risk-related
benefits created through introducing entirely new ways of inspecting bridges and visualising information,
there also remain hindrances to the wider deployment of UAVs. This study is to provide a context for use of
UAVs for conducting visual bridge inspections, in addition to addressing the obstacles that are required to be
overcome in order for the technology to be integrated into current practice.