With budgets that tend to favor new construction, many DOTs are finding it necessary to prioritize the most urgent repairs. But infrastructure decay is not always easily visible. And deferred or inadequate maintenance may occasionally have catastrophic consequences for U.S. bridges, 40 percent of which are at least 50 years old, and 9.1 percent of which are considered structurally deficient. A new remote sensing methodology may make the job of decay detection easier, and possibly more accurate.
New infrared cameras can identify various tailpipe emissions in real time from vehicles passing at highway speeds. By analyzing the ratios of different pollutants, the technology can also distinguish between high-emitting vehicles that are functioning normally—i.e., vehicles that are burning more fuel to carry heavier loads or more passengers—from those that have mechanical problems that need to be dealt with.