What should you never assume about posted heights at bridges or underpasses?

It is essential to remember that posted heights at bridges or underpasses may not always be completely accurate due to a variety of factors, such as changes in road surface conditions, settling of structures, or variations in measurement. For large vehicles, relying solely on these posted heights could lead to serious accidents or damage. Therefore, drivers, especially those operating larger vehicles, should always verify their vehicle's height and proceed with caution, rather than trusting the posted numbers implicitly. Ensuring clear communication and understanding of such information is crucial for safe navigation through areas with height restrictions.