3 Techniques for Cross-Examining the Government’s Breath Test Expert

The Short and Simple Approach

This approach limits the cross-examination of the Technical Supervisor to no more than five questions.  The idea is to avoid arguing science with a scientist, especially if you don’t have the background to do so.  In breath test trials, attorney Jimmy Angelino often limits his cross-examination to the following:

Q:  Isn’t it true that the breath testing program has one major flaw?

Q:  The flaw is that you cannot tell this jury what my client’s BrAC was at the time he was driving, right?

Q:  My client could have been below .08, at .08 or above .08 when he was driving his car, correct?

Q:  If you do a mathematical calculation to try and determine what his BrAC was at the time he was driving, it would amount to nothing more than a guess, correct?  (Note: The Tech Sup may argue that it’s an “educated guess,” but point out that it’s still a guess.)

Breath Testing Is Quick and Cheap

The idea here is to point out that breath testing is quick and cheap but lacks the accuracy of blood testing.  This sets up a closing argument that your client was not given the option of the more accurate test due to cost.  This is an approach Dallas attorney Gary Redman often uses with great success.  The following is reprinted with his permission:

Q:  A breath test is not the only way to test a person’s alcohol level, is it?

Q:  You could test a person’s urine?

Q:  You could have drawn blood?

Q:  A qualified technician would have to draw the blood?

Q:  Or a nurse?

Q:  The blood would then be sent to a laboratory?

Q:  Another qualified person would test the blood?

Q:  This is a very accurate way of testing a person’s blood alcohol concentration?

Q:  It is the ONLY way to accurately test a person’s BLOOD alcohol concentration?

Q:  A blood test is not cheap, is it?

Q:  You have to wait for a blood test result, right?

Q:  It could take weeks to get the result back?

Q:  It’s not quick, is it?

Q:  Another way to test a person’s alcohol level is to use a breath test?

Q:  With a breath test, you get a result right then?

Q:  A subject blows into the machine?

Q:  The machine gives a result?

Q:  This is a lot quicker than a blood test?

Q:  With a breath test, you get the results immediately?

Q:  You don’t have to wait weeks?

Q:  Which test is the cheapest to administer?

Q:  And breath is by far the quickest to administer, correct?

Q:  The machine that analyzes blood costs about $100,000?

Q:  The cost of a breath test machine is about $6000?

Machines Make Mistakes and Need Repairs

Juries understand that machines break and need repairs.  Pointing out the lack of routine repair or simple cleaning of the machine in your case is a simple way to cast doubt on the accuracy of the Intoxilyzer. Technical Supervisors often do not bring the repair or cleaning records of the machine in question to court with them and cannot tell you when the light source was last changed or whether the machine has ever been cleaned.  The records they bring are typically the maintenance records which simply list on-site inspections and solution changes.

Q:  Have there been instances when the machine printed out a test result and it was later determined to be invalid?

Q:  You perform what are called “modem checks” where you call the machine and perform a series of diagnostic tests over the phone, correct?

Q:  Have you had instances where the modem check indicated that the machine was fine but you later discovered that it had a problem?

Q:  That source lamp can collect dust?

Q:  When was the last time the source lamp was cleaned?

Q:  When was the last time the source lamp was replaced?

Q:  The filter wheel is supposed to turn at a speed of 2200 to 2300 revolutions per minute?

Q:  When was the last time the speed had to be adjusted?

Q:  When was the last time the filter wheel was cleaned?

Q:  Has the filter wheel ever been replaced?

Q:  What about the sample chamber, has it ever been cleaned out?

Q:  When was the last time the machine was brought in and re-calibrated?


Excerpted from the free eBook Attacking Breath Test Results by Deandra M. Grant and Kimberly Tucker.