Updated July 2026

The Short Version

Field sobriety tests and breath tests are the backbone of most DWI cases, and they are far less reliable than the police make them sound. Roadside balance tests are subjective and easy to fail sober. Breath machines can be wrong when they are not certified, calibrated, or operated correctly. Challenging these tests is often how a DWI gets dismissed or reduced. Call (505) 247-1973 for a free review.

The 10-day clock. If you were arrested for DWI, you have only 10 days from the date of arrest to ask for an MVD hearing. Miss that deadline and the revocation of your license becomes automatic, no matter what happens in court. See how the MVD hearing works →

Most people assume that if they failed the roadside tests or blew over the limit, the case is over. It is not. These tests are science, and science can be done wrong. A machine that is not maintained, an officer who skips a step, or a medical condition you cannot control can all produce a result that looks damning but does not hold up. Mr. Nieto knows where to push.

The Standardized Field Sobriety Tests

On the roadside, officers usually give three standardized tests:

Horizontal gaze nystagmus — following a pen with your eyes while the officer watches for involuntary jerking.
Walk and turn — nine steps down a line, a turn, and nine back, while following instructions.
One-leg stand — balancing on one foot while counting.

These tests are supposed to be given and scored in a very specific way. In the real world, they are done on uneven ground, in bad lighting, in traffic, by people who are nervous, injured, overweight, older, or dealing with a medical issue. Being unable to balance on one leg is not proof of intoxication, and these tests are often more subjective than the officer admits.

Are the Roadside Tests Even Required?

Field sobriety tests are voluntary. You are generally not required to perform the roadside balance and eye tests, and politely declining them is not the same as refusing the official chemical test. The chemical breath or blood test after arrest is the one that triggers New Mexico’s implied consent law, where refusing carries real penalties. See test refusal to understand that difference, because it matters.

Talk to Mr. Nieto. The first call is free, and he answers it himself.

Call (505) 247-1973

Why Breath Tests Are Not Foolproof

The breath machine can look like hard science, but its result depends on many things going right:

The machine has to be properly certified and calibrated, and records must prove it.
The officer must observe you for a set period before the test, usually to make sure you do not burp or bring mouth alcohol up, which can spike a reading.
Medical conditions like acid reflux, diabetes, and certain diets can affect results.
Your alcohol level may still have been rising, so the reading at the station may be higher than it was when you were actually driving.

A reading of .16 or higher can make a DWI aggravated, so challenging the breath test can do more than win the case, it can strip away mandatory jail.

Blood Tests Can Fail Too

Blood tests are treated as the gold standard, but they have their own weak points. The blood must be drawn by a qualified person, stored and preserved correctly, and tested without contamination or delay. A broken chain of custody, an expired preservative, or a lab error can all make a blood result unreliable. Mr. Nieto requests the full records and has them reviewed, because the paperwork often tells a different story than the number on the report.

How Mr. Nieto Challenges DWI Tests

Mr. Nieto gets the calibration and maintenance records for the breath machine, the officer’s training and certification, the video of the roadside tests, and the full lab file for any blood draw. He looks for the missed observation period, the uncertified device, the skipped step, and the medical explanation. When a test does not hold up, the evidence can be suppressed or its weight destroyed, and that is often what turns a DWI into a dismissal or a reduction. Start with the MVD hearing to protect your license while the case plays out.

Those test records matter just as much in an Albuquerque case. An Albuquerque DWI lawyer uses them in Metro Court and at the license hearing.

Why Mr. Nieto

The Lawyer Who Has Actually Been There

Art Nieto has personally tried cases from DWI to first-degree murder in nearly every judicial district in New Mexico. He started as a public defender, never a prosecutor, has been licensed to practice law in New Mexico since 2000, and has run his own firm since 2003. When you call, you work with Art himself.

25+Years in New Mexico courtrooms

~100Jury & bench trials

1Lawyer on your case, start to finish

2Offices: Albuquerque & Santa Fe

Common Questions

Do I have to do field sobriety tests in New Mexico?

No. The roadside field sobriety tests, like the walk and turn and one-leg stand, are voluntary, and you can politely decline them. That is different from the official breath or blood test after arrest, which is covered by implied consent and carries penalties for refusal. Declining roadside tests is not that kind of refusal.

Can field sobriety tests be wrong?

Absolutely. These tests are subjective and easy to fail while completely sober. Uneven ground, bad lighting, nerves, injuries, weight, age, and medical conditions all affect performance. They are supposed to be given and scored in a precise way, and officers often cut corners, which Mr. Nieto can expose.

How accurate is the breath test?

Less accurate than it looks. A breath result is only reliable if the machine is certified and calibrated, the officer observed you for the required period, and no medical or timing issue skewed it. Acid reflux, diabetes, mouth alcohol, and a rising alcohol level can all inflate a reading. These are real, provable challenges.

Can a blood test result be challenged?

Yes. Blood evidence depends on a proper draw, correct storage, an unbroken chain of custody, and accurate lab testing. An expired preservative, a handling error, or a lab mistake can make the result unreliable. Mr. Nieto requests the complete lab file and has it examined for exactly these problems.

Why does a high breath test matter so much?

Because a breath or blood result of .16 or higher can make a DWI aggravated, which adds a mandatory 48 hours in jail on a first offense. That means challenging the breath test is not just about winning the case, it can remove the aggravation and the mandatory jail that comes with it.

The tests said I was over the limit. Is my case hopeless?

No. Failing the roadside tests or blowing over the limit does not end the case. Those results have to hold up to scrutiny, and often they do not once the records and video are reviewed. Many DWIs that looked airtight are dismissed or reduced after the testing is challenged. It is worth having Mr. Nieto look.

Field Sobriety & Breath Tests in New Mexico