What is the maximum speed limit for passenger vehicles on Texas highways?

The maximum speed limit for passenger vehicles on Texas highways is indeed 70 mph. This speed limit is typically seen on rural interstate highways where the design and condition of the roadway can accommodate higher speeds, plus it allows for efficient traffic flow while maintaining safety standards.

It's important to note that certain areas may have different posted limits based on specific conditions, such as construction zones or urban areas, but under normal circumstances, the 70 mph limit is standard for passenger vehicles on Texas highways. This limit is in place to ensure that motorists can travel safely while allowing for faster transportation across longer distances.

The other options represent speed limits that may apply in different contexts or states, or they might be outdated for specific types of vehicles or road conditions. However, for general passenger vehicles on Texas highways, the correct and upholdable limit is 70 mph.