The Transportation Research Board in 2019 published two documents presenting wide-ranging perspectives on matters of importance to the future of the nation’s transportation system and its capabilities to support our continued prosperity. The first of these documents, Renewing the National Commitment to the Interstate Highway System: A Foundation for the Future (CIHS), the product of a congressionally mandated study, presented a series of recommendations for government actions needed “to upgrade and restore the Interstate Highway System to fulfill its role as a crucial national asset, serving the needs of people, cities and towns, businesses, and the military while remaining the safest highway network in the country” (CIHS, p. viii). The second document, Critical Issues in Transportation 2019 (CIT2019), was prepared by the TRB Executive Committee to frame high-level questions that can be addressed during the next 5 to 10 years through research, policy analysis, and debate to help society prepare for potentially unprecedented changes likely to affect our transportation system’s service to individuals and society (CIT2019, p. 2).

Considering the contributions our highway system makes to the nation’s economy and well-being and the age of many of the physical assets comprising this system—pavement, bridges, culverts, embankments, and more—these reports highlight the importance of knowledge of asset condition and likely reliability. Such knowledge is essential to allocating maintenance resources, determining when asset renewal or replacement is prudent, and thereby ensuring the system’s continued high performance. Regarding the Interstate System, for example, a recommendation was made that “… Congress should direct U.S. DOT and FHWA to join with the states to assess the foundational integrity of the system’s pavements and bridges, and identify where full reconstruction is needed based on accepted life-cycle cost principles” (CIHS, p. 208). More generally, “…improved maintenance strategies are needed to cost-effectively enhance infrastructure performance over its full life cycle” (CIT, p. 21).

This knowledge of asset condition and service capability is inadequate for much of the highway system. People responsible for system asset management know that aging of materials, variations in weather and climatic conditions, normal usage and such unusual events as vehicle crashes and seismic shock, erosion of foundation soils, and other factors contribute to deterioration of asset condition and service capability, but they often cannot be certain about the rate of deterioration or the damage that has accumulated. Deterioration and damage, generally hidden from observation within and around massive, earth-bound structures, may be partially revealed by observation and testing through excavation or drilling into the structure, but such methods introduce new damage and can contribute to more rapid deterioration.

Continuing technology developments—for example, remote sensing (ground-penetrating radar, light detection and ranging (LIDAR), and acoustic emissions detection), embedded sensors, and others—seem promising, but high costs of data collection and processing may outweigh the benefits to be gained through cost and risk reduction and improved asset management generally. This tradeoff of data collection and processing costs versus asset management benefits to be gained is particularly troublesome with respect to the foundations of transportation system infrastructure, the condition and capabilities of materials beneath and adjacent to pavements, footings, walls, and embankments. Research is needed to identify, develop, and facilitate cost-effective use of methods for non-destructive in situ inference, direct measurement, and testing of foundational integrity, condition, and service capability of highway system assets, as well as to guide further research and development for advancing measurement, testing, and monitoring practice.