This law will accomplish absolutely nothing, overall. Clean your act up for a couple of days prior to being tested, for anything other than pot, and you'll test clean. Some of the most harmful drugs are out of your system in a couple of days. Alcohol being one of the main "drugs of choice", one of the most harmful to both the individual, the family, and society in general...and one of the fastest to get out of your system. Unless they want to test hair, and that ain't $20 per.
Looks good on paper, and politically it pacifies some, but in reality nothing will be accomplished with an initial screening. Random testing would be another matter entirely.
So here's what will happen: The law will be challenged, Florida will spend gobs of taxpayer dollars fighting it, possibly all the way to the Supreme Court, and it will be struck down, and even if it's not (highly unlikely), many, many $$$$ will be spent in the process.
Time, money, and effort could be better spent trying to solve the root of the problem. End of discussion on my part...