Downvotes perhaps because lying to a cop, or resorting to yes-it-is-vs-no-it-isnt with authorities is stupid. He stopped you, and has far more weight in court regarding whether conditions were safe for that speed than you do. Doing 54 in a 40 is fast, and neither the cop nor judge will agree with your assessment.
Cops may let you go faster, and they're authorized to do so if conditions fit ... but they also get to say "the speed limit is a limit" and charge you accordingly. There are a few areas where speed limits are broadly understood, even codified, as suggestions (they post limit signs to elicit federal funds, but on a dry sunny day all they care is you can stay on the road and can stop in time), but nearly everywhere else just realize speed limits are just that, and if you violate them don't be surprised if the jurisdiction decides to profit off your actions.
Cops may let you go faster, and they're authorized to do so if conditions fit ... but they also get to say "the speed limit is a limit" and charge you accordingly. There are a few areas where speed limits are broadly understood, even codified, as suggestions (they post limit signs to elicit federal funds, but on a dry sunny day all they care is you can stay on the road and can stop in time), but nearly everywhere else just realize speed limits are just that, and if you violate them don't be surprised if the jurisdiction decides to profit off your actions.