The New York Times says not to trust breath test machines. I agree. There are many problems with breath test machines. They produce an estimate of alcohol based on the universal human being. The problem is there is no such thing. People have varying blood breath partition ratios, hematocrit densities, and breath temperatures. All of these factors affect the alcohol estimation the breath test machine produces. Modern machines are capable of measuring the breath temperature of a person but Texas chooses not to use this technology. A criminal conviction is serious, too serious to base a final decision on an estimate that lacks the parameters that are unknown when a person blows into it.