Speed limit question

Where does a speed limit sign take effect? I’d always imagined that the new limit was in effect once one broke the plane of the sign, but I read an account here once of a judge dismissing a ticket on the basis of a new limit taking effect once the speed limit sign became visible. I’m most interested in Texas law.

There’s probably an actual law, but it seems like it could argued either way. Especially in adverse weather conditions. Or entering the road/highway whatever in between two different speed limits.

Threads on GQ before have demonstrated that the speed sign takes effect where the sign actually physically is. Which, for some places, creates some interesting situations where due to maximum speeds of one zone (say, 35) and minimum speeds of the next (say, 40), it’s impossible to drive through legally.

An example of that, perhaps, SenorBeef?

Usually a minimum speed limit says unless otherwise posted.