based on the consideration of condition and other factors that will allow for routine, underwater, and nonredundant steel tension member inspections that would allow some inspection intervals to be up to 72 months (23 CFR 650.311). The regula- tion requires written reports to FHWA of critical findings identified during inspections and provides minimum criteria for what a critical finding is, to maintain national consistency (23 CFR 650.313). The rule also introduced “Specifications for the National Bridge Inventory, SNBI” (23 CFR 650.317) (FHWA 2022a) to replace the ‘‘Recording and Coding Guide for the Structure Inventory and Appraisal of the Nation’s Bridges (Coding Guide)” introduced in 1995 (FHWA 1992). This is a major change including an expansion of component-level ratings to include bridge railings and their transi- tions, bearings, joints, channel, channel protection, and scour besides deck, superstructure, substruc- ture, culvert, and channel. A larger set of data is collected not only ensuring highway bridge safety but other considerations, including oversight of the National Bridge Inspection Program reporting to Congress emergency response administering a risk-based, data-driven, performance management program the National Performance Management Measures for Assessing Bridge Condition regulation (National 2017) and providing quality data through clarity and ease of use (FHWA 2022a). Full implementation of these changes is expected by Calendar Year 2028 (FHWA 2022b) due to time required to modify relevant software used by bridge owners, development of federal metrics and data-collection mechanisms, development of reg- ulation and policy changes in owner agencies, and so on. These changes to NBIS will not only continue the focus on improving safety but will move toward quality data collection for making better bridge management decisions, and thus supporting the asset management requirements. Role of Advanced Technologies in Bridge Inspection As noted earlier, the public expects not only safe bridges, but also reliability and uninterrupted mobility. This may be accomplished by supple- menting visual inspections with advanced NDE and structural monitoring technologies as well as uncrewed aerial systems (UAS) or robotic tech- niques so that bridge inspection does not require bridge closures that affect the mobility of the trav- eling public. These methods, combined with risk- based inspection intervals, will likely become preva- lent soon, especially with the implementation of the new NBIS. These advanced technologies have a big role to play in the coming years. Augmenting bridge inspections through these methods has the poten- tial to improve durability and minimize life cycle costs. The most practical of these systems are being used by owners during “in-depth” or “special” inspections or implemented for long-term monitor- ing. Some examples of advanced systems that are discussed in this special issue include the following: Ñ Inspection during and before opening to traffic is very important in ensuring durability and maintaining expected service life. The use of light detection and ranging (LiDAR), augmented reality, and technology fusion for data visualiza- tion of inspection data plays a major role. Sanei et al. (2023) summarize available technologies for quality control of reinforced concrete struc- tures during construction and focuses on using Red Blue Green Depth (RGBD) cameras for this purpose (see Figure 2). Ñ In recent years, the use of UAS has been intro- duced to improve data consistency, work effi- ciency, inspector safety, and cost-effectiveness during routine inspections. Advanced multi- sensor robotic platforms, such as ground-based systems (UGS) and uncrewed water-based systems (UWS), are also being used increasingly Figure 2. Use of RGBD camera for construction inspection. J A N U A R Y 2 0 2 3 • M AT E R I A L S E V A L U AT I O N 27 2301 ME Jan New.indd 27 12/20/22 8:15 AM COURTESY: DR. MOREU, UNIVERSITY OF NEW MEXICO

for similar purposes. A futuristic view of using UAS-based NDE for elevated structures (bridges, buildings, dams, power plants, tunnels, etc.) is discussed in detail by Chen et al. (2023). These systems, including human-robot systems, have the potential to transform bridge inspections in the future to minimize impacts to traffic at bridge sites (see Figure 3). Ñ Similarly, modern underwater inspections are increasingly reliant upon new technologies and nondestructive testing methods beyond visual inspection (see Figure 4). These technologies are used in conjunction with conventional diving inspection to gain a broader overall picture of the asset and its condition, increasing efficiency while lowering risk in the process. Severns (2023) discusses the more modern underwater inspec- tion approach, emphasizing the modern NDT technologies utilized as well as their benefit to the process. Ñ Improving the accuracy in the detection and characterization of deterioration and defects using NDE methods is essential for the condition assessment of reinforced concrete bridge elements. At the same time, improving the speed of NDE data collection and interpretation— allowing economical periodical evaluation—will enable capturing of deterioration processes and defect formation leading to the development of more realistic deterioration, predictive, and life cycle cost models. Ultimately, those will lead to better bridge management. Gucunski et al. (2023) provide an overview of the current practice of bridge evaluation by NDE methods, recent efforts to improve the speed of NDE data collection through automation and robotics, and improved condition interpretation through advanced visu- alization and combined analysis of results of multiple NDE technologies. Ñ Deployment of large-scale wired and wireless sensor networks for bridge structural monitoring (SM) is also being accepted by more and more owners. Augmented by use of artificial intelli- gence (AI) and deep learning for data analysis, Figure 4. Underwater ultrasonic inspection of steel using remotely operated vehicle. FEATURE | BRIDGEINSPECTION Figure 3. Climbing robot with NDE capabilities assisting with bridge inspection. 28 M AT E R I A L S E V A L U AT I O N • J A N U A R Y 2 0 2 3 2301 ME Jan New.indd 28 12/20/22 8:15 AM COURTESY: RICH ARRIETA, NAVAL INFORMATION WARFARE CENTER COURTESY: DR. GENDA CHEN, INSPIRE UNIVERSITY TRANSPORTATION CENTER