What statute were you cited for?
Was it LRS 32:104?
If that is the case, then here you go:
Louisiana Revised Statute •Title 32. Motor vehicles and traffic regulation
§104. Turning movements and required signals
A. No person shall turn a vehicle at an intersection unless the vehicle is in proper position upon the roadway as required in R.S. 32:101, or turn a vehicle to enter a private road or driveway, or otherwise turn a vehicle from a direct course or move right or left upon a roadway unless and until such a movement can be made with reasonable safety.
B. Whenever a person intends to make a right or left turn which will take his vehicle from the highway it is then traveling, he shall give a signal of such intention in the manner described hereafter and such signal shall be given continuously during not less than the last one hundred (100) feet traveled by the vehicle before turning.
C. No person shall stop or suddenly decrease the speed of a vehicle without first giving an appropriate signal in the manner provided herein to the driver of any vehicle immediately to the rear when there is opportunity to give such signal.
D. The signals provided for in R.S. 32:105(B) shall be used to indicate an intention to turn, change lanes or start from a parked position and shall not be flashed on one side only on a parked or disabled vehicle, or flashed as a courtesy or "do pass" signal to operators of other vehicles approaching from the rear.
Acts 1962, No. 310, §1. Amended by Acts 1963, No. 33, §2; Acts 1970, No. 538, §1.
Notice it does not mention any exception to the rule of you having to signal if you were in a turning lane. So basically, your only defense here is if you were able to refute the officer's testimony that you did signal before you turned. Also keep in mind that by you arguing that you were in a turning lane and therefore (according to your logic) you did not feel the need to signal, you are indirectly admitting guilt. So the defense that your using will end up getting you the same guilty plea you were trying to avoid.
Even if you were cited for a local/Municipal Statute, it will most likely have similar language that requires you to signal before turning regardless of whether you are in a turning lane or not.
