Final answer:
Texas law does require motorists to drive at safe speeds for current conditions, even if it's below the posted speed limit; this is known as the basic speed rule, confirming the statement as true.
Step-by-step explanation:
The statement that Texas law prohibits operation of a vehicle at a speed greater than is safe under prevailing traffic and road conditions, regardless of the posted speed limit, is true. This is known as the basic speed rule, which states that irrespective of the posted limit, drivers must adjust their speed to match road conditions such as weather, traffic, visibility, and the surface quality of the road. Even if you are driving at the posted limit, if conditions dictate that a slower speed is necessary for safety, then you are required by law to slow down. On the other hand, if you happen to be driving slightly over the speed limit, law enforcement typically allows a small margin, recognizing that speedometers aren't always exact and that a de facto speed limit exists, being slightly higher than the post.