# Personal BAC Testers vs. Police Breathalyzers | TadLaw

Some cautious Harris County residents will do anything to avoid an arrest and conviction for driving while intoxicated – including purchasing their own personal breathalyzer or breath-testing instrument.

On the one hand, this can be seen as a responsible act: it is presumed that an individual in the possession of one of these devices will use it after a night out to determine whether he or she is safe to drive or whether he or she should hail a taxi. On the other hand, though, these devices may not be effective at preventing the user from being arrested and [charged with DWI](https://tadlaw.com/resources/texas-dwi-resources/first-offense-dwi/) in Texas.

## Differences Between Personal & Police Breathalyzers

Any comparison between personal breath testing devices and the breathalyzer device used by law enforcement in DWI investigations must recognize that these are two different machines and that law enforcement breath testing devices have numerous benefits over personal devices:

- Law enforcement testing devices typically do not show a “false positive” for someone who is diabetic or on a low-calorie diet;
- The readings on personal devices are not as accurate as those on law enforcement devices;
- Professional breathalyzers remain accurate (or should remain accurate) over many tests whereas personal devices may give varying readings if multiple tests are completed in quick succession.

Not only this, but it must be remembered that:

- Your breath alcohol concentration (BAC) follows a “bell curve” trajectory that peaks some time after you stop drinking. So if you stop drinking at the bar and test your BAC using a personal device, the reading of that device may not correlate much to a police officer’s preliminary breath test device or breathalyzer when you are stopped on the way home 30 minutes later.
- Neither the officer nor the prosecution needs to show that your BAC is any specific level in order to[arrest and convict you of driving while intoxicated](https://statutes.capitol.texas.gov/docs/PE/htm/PE.49.htm/). Even if your own personal breath tester shows a BAC of 0.04 – half of the “legal limit” – you may still be convicted of driving while intoxicated if the prosecution can show (1) you were under the influence of alcohol and/or drugs; and (2) this made you unable to safely drive a vehicle.

## Does It Pay to Purchase a Personal Breath Tester?

![Houston DWI Attorney Tad Nelson](https://tadlaw.com/wp-content/uploads/2020/07/sidebar_tad-150x150.jpg)While purchasing a personal breath tester may provide you with some indication of your BAC level after a night out on the town, it cannot guarantee that you will not be arrested, charged, and/or convicted of driving while intoxicated.

One step that you *can* take that can significantly improve your chances of succeeding in your DWI case is retaining the services of the knowledgeable and experienced [Houston DWI defense law firm](https://tadlaw.com/contact-us/), the Law Offices of Tad Nelson & Associates.

Our law firm is well-versed in legal issues that arise in DWI cases, and we are prepared to assist you in achieving the best possible outcome in your case. Contact the Law Offices of Tad Nelson & Associates in Galveston today for experienced legal assistance.

For a free legal consultation, call [(281) 280-0100](tel:+12812800100) today

## The Law Office of Tad Nelson & Associates

### Houston • Clear Lake • Galveston • League City

Call or text [(281) 280-0100](tel:+12812800100) or fill out our [Free Case Evaluation Form](https://tadlaw.com/contact-us/) to get started

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Source: https://tadlaw.com/blog/personal-bac-testers-vs-police-breathalyzers/