Collin County's courthouse is located in McKinney, Texas. If you are pulled over after having a couple of drinks and the police officer smells alcohol in one of Collin County's cities, like McKinney, Plano, Frisco, Allen, etc. than you will likely be asked to perform a series of tests. The police officer may tell you that he or she is making sure that you are OK to drive, and that may be the case. However, in my experience he is simply trying to build evidence for the State to use at trial to show you were intoxicated.
Intoxication is defined two ways in Texas. A. Having a blood alcohol concentration level of .08 or higher at the time of driving; or B. Having lost the normal use of your mental or physical faculties due to the introduction of alcohol, drugs, a controlled substance, a dangerous drug, or any combination thereof.
The police officer has a much easier job of making an arrest than the State does at trial. The reason is the police officer only has to have probable cause to make an arrest while the State has to prove the allegations at trial beyond a reasonable doubt.
That is why it is critical to have an experienced DWI trial lawyer.