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How Police Detect Drunk Drivers


Often times, the trajectory between the police pulling one over and being arrested for a DUI can happen very quickly. It is important to know what the cops look for when they are scanning for drivers who are under the influence. This blog lists some of the main factors the authorities look for when pulling individuals over for a DUI.

Erratic or Unusual Driving

The first thing the cops usually look for while scanning the streets is if a driver is exhibiting erratic driving techniques or is endangering themselves or others while on the road. Some driving behaviors that the police look for are:

  • speeding, slowing down for no reason
  • drifting between the lanes without direction
  • swerving, and stopping randomly

The individual may have a valid excuse for the way they are driving. And if that is the case, the officer may let them off with either a warning or ticket. However, if the police suspect the driver of being under the influence of drugs or smells alcohol on their breath, they will probably ask you to take other tests.

Field Sobriety Tests

If the police officer has probable cause to believe that you have been drinking or are under the influence of drugs or narcotics, they can ask you to step out of the car and perform some field sobriety tests. The purpose of such tests is to further solidify whether a driver was under the influence. The officer will ask you to take tests such as:

  • standing on one leg for a period of time
  • walking in a straight line
  • reciting a list of numbers or letters.

These tests aim to judge your coordination and cognitive state. The police officer will also be looking closely to see if pupils are dilated. Individuals have the right to refuse to perform the field tests. However, if the police suspect intoxication, they have the right to arrest the driver.

Chemical Blood Alcohol Level Tests

Finally, if the driver has failed the field sobriety tests, police officers will usually ask them to take some form of test to determine blood alcohol levels. They usually check blood, urine, or the breath to determine alcohol levels. Some states give the driver the option of choosing which test they would like to submit, while others do not. If the police finds that the blood alcohol level is above 0.08%, they have the right to charge the driver with DUI. Unlike field sobriety tests, individuals do not have the right to refuse to take blood alcohol level tests. If a driver refuses a blood test after a lawful arrest, their driver’s license will be automatically suspended.

If you or someone you know has been arrested for a DUI, contact MayesTelles today! Our experienced Phoenix DUI attorneys can review your case. We have helped many of our clients avoid DUI arrests.

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