While on this point, people often ask whether they should take a chemical test when arrested for driving while intoxicated. Our general response as defense attorneys is NO, because there are a lot of things that can go wrong with chemical testing. Both breath testing and blood testing are inexact sciences, and there are lots of human and mechanical errors that can happen to give you a much different result than your actual blood alcohol content. The test is also completely in the hands of the State, and officers and the laboratory employees can tamper with or mishandle the evidence. Also, if your blood alcohol content is above the legal DWI limit of .08, you are only producing evidence against yourself.
However, if you are sure your blood alcohol content is zero or close to it, it might be to your advantage to take such a test assuming everything goes right. Also, there is a shorter ALR license suspension for a chemical test failure, as you are implied by law to consent to chemical testing upon request by law enforcement. Additionally, Grayson and Collin County have a “no refusal” policy for driving while intoxicated, and a warrant will almost always be applied for by the officer and obtained from a judge. They will likely take you to the hospital and draw your blood with a warrant upon refusal. So, the general answer is still that one should refuse a breath or blood test upon request as far as a DWI case is concerned, but they will normally get your blood through search warrant. However, there are challenges to the search warrant that can be had if it is not proper.