(I also posted this in the experts forum, but this gets more traffic.)

Has anyone dealt with Charlie Foster from DeSoto as a defense witness on DWI? He is listed as a defense expert in a DWI case I have. The notice of expert says that he will testify that the officer failed to administer the HGN (which will be obvious) and did not administer the walk and turn or the one leg stand tests correctly, and it is his opinion that the officer cannot use the test as justification for arrest. I think I can keep that opinion out at a 702 hearing because that's bogus expert testimony - whether the officer can use those as justification for arrest is purely a question of law. What are your thoughts?

I have been told by a fellow prosecutor that there is a police officer they dealt with on several DWIs who was with Addison Police Dept. several years ago.

JAMIE

Hypothetically if the officer believed a flawed test, but her belief in the test was reasonable under the circumstances, does she have probable cause for arrest or doesn't she?

PC to arrest doesn't have to come from SFTs alone. Driving facts, behavior, appearance of the suspect will also be involved. Furthermore, you have to ask whether the "incorrectly" performed tests were thus misleading or not. For example, if the manual says to have the person stand on one foot and count to 30, but you ask them to count to 10, you've done it wrong, but made it easier. If I instruct the person to hold their arms out for balance on the walk and turn, I've given an improper test, but allowed them an advantage. In either case, if the person still fails the test, I'd still have PC, even though I failed to follow the NHTSA manual. If I tell the person to do a handstand and recite the Greek alphabet backwards, then their failure to complete the test is probably meaningless (and I think most juries would probably realize it, as well).

Alex and W, you're both absolutely right. I know I can argue all that - the PC comes from many sources, not just the SFST's, and many cases have held that SFST's done incorrectly are still useful to the officer in terms of observations of the defendant. My frustration is that he is planning on drawing a conclusion - that the officer can't use those in his PC - which is absolutely false. I can understand them arguing for a jury to give the tests less weight in deliberating, but I think it's ridiculous to suggest that they be completely ignored as evidence. And since there is nothing illegal in the administration of them, and they do not require expert testimony, there isn't a legal basis for ignoring them. But they want the jury to think that there is.

BTW, I'm not at all conceding that they were even done incorrectly. I think they deserve the full weight they were designed for.