What is an essential factor to document in the case of a breath test failure?

Documenting the presence of witnesses during a breath test is essential because it can provide additional credibility to the test results and the process followed during the testing. Witnesses can corroborate that the test was administered properly, that there was no interference, and that all procedures were adhered to according to legal standards. This is particularly important if the results are challenged later in court. Witness presence can also help to establish that the suspect was treated fairly during the testing process.

On the other hand, while aspects like test location, equipment calibration, and evidence of refusal are important in the overall context of DWI investigations, the primary focus on witness presence highlights the accountability and transparency of the procedures followed during the breath test.