SFSTs: For Alcohol only? Or do they apply to drugs?

Defense attorneys periodically challenge the use of the Standardized Field Sobriety Test battery for non-alcohol drugs. This issue recently surfaced on the Impaired Driver Forum. My comment, which is posted below, was used by Mark Neil of the National Traffic Law Center at a presentation at the annual IACP DRE conference in Pittsburgh last week. The SFSTs were developed to detect the presence of alcohol at impairing levels. It's universally accepted that Alcohol is a drug. So, one way of looking at the issue is that the SFSTs were in fact designed to detect the presence of drugs at impairing levels. The primary differences between the drug alcohol and the non-alcohol drugs are: Breath test for alcohol; odor of alcohol, simple pharmacokinetics, statutorily prohibited levels (such as .08), that are based in part on impairment, and commonly known signs and symptoms of influence. Those
who challenge SFSTs for non-alcohol drugs frequently put the cart before the horse: for example, by suggesting that different SFSTs should be used for different drugs! I find that sadly amusing.

Also, the SFSTs are NOT driving tests. They do, however, assess the person's ability to pay attention, remember instructions, divide attention, and perform psychomotor maneuvers requiring both fine and gross motor control. It's these abilities that are important to driving.