How Do the Police Determine If You’re Under the Influence?

There are three methods the police usually use to determine whether an individual is too impaired to be operating a vehicle (vehicles include bicycles). They are as follows, in order of usage by the police:

• Observation - Most of the time, this is what initiates the police’s action.  If they observe a driver swerving in and out of their lane or speeding, this is sufficient to pull the driver over.  Once the officer pulls the driver over, the officer can make a better assessment of why the driver was driving in that manner.  If the driver has blood-shot eyes and reeked of gin, there’s no chance, the officer will continue with the next method.
• Sobriety Tests - The officer will make the driver perform some mental and physical tasks; ones that require intense concentration and/or physically balance/dexterity.  They including asking the driver to recite the alphabet backwards (freakin’ hard) or balancing on one foot for 30 seconds or asking the driver to follow a pen with his/her eyes.  If you can’t recite, can’t balance, or can’t follow (smoothly and naturally), the driver is in deep doo-doo.
• Blood-Alcohol Level (BAC) Test - There are multiple ways to perform this test.  It can be done by testing urine, breath, or blood.  Testing by breath (Breathalyzer) is usually done on-site.

In the end, most arrests will result in some sort of BAC test.  That is the quantitative evidence that will seal the deal.