Pennsylvania Field Sobriety Testing

September 16, 2010

In Pennsylvania, an officer often conducts field sobriety testing prior to asking a driver to submit to a roadside breath test and making an arrest, whether the driver is suspected of intoxication during a traffic stop, sobriety checkpoint or saturation patrol. In October 2008, Pennsylvania began the Checkpoint Strikeforce Initiative, which requires each of the 15 regional state police troops to conduct random sobriety tests of drivers on most weekends. The State Police Commissioner noted that the program contributed to a record number of DUI arrests that year.

Standardized Field Sobriety Testing

In the 1970s, the National Highway Traffic Safety Administration (NHTSA) began to fund studies aimed at the standardization of tests to assess driver impairment. The research commissioned by NHTSA identified three tests that were supposedly most predictive of blood-alcohol content (BAC) as revealed by laboratory tests. Statistical analysis showed the Horizontal Gaze Nystagmus (HGN), sometimes called the pen test, to be the most effective. The other two tests identified were the Walk-and-Turn (WAT) test and the One-Leg Stand (OLS) test.

The Horizontal Gaze Nystagmus Test

The HGN test consists of the officer observing the eyes of the driver while he or she follows a pen, flashlight or other small object. The officer holds the object in front of the driver and then moves it from side to side. HGN is an involuntary movement of the eyes that naturally occurs when they are rotated at high peripheral angles. But HGN is exaggerated and may occur at lesser angles if the person is impaired by alcohol.

In an HGN test, the examiner is looking for indicators of impairment from each eye, such as:
- Inability to follow the moving object smoothly
- Distinct jerking at maximum deviation
- Onset of jerking within 45 degrees of center

The accuracy of the HGN test has been questioned. Research funded by NHTSA indicates a proper identification rate of 88 percent, but false positives cause a margin of error. Pennsylvania courts have deemed HGN test results to be scientific evidence based on the principal that alcohol consumption causes (or exaggerates) nystagmus. But the Superior Court of Pennsylvania has repeatedly declined to recognize HGN test results as sufficient independent proof of intoxication.

Walk-and-Turn Test

The WAT test is a divided attention test, in which the driver is instructed to take nine heel-to-toe steps in a straight line, then turn on one foot and return to the starting point in the same manner. The WAT test examiner is looking for a variety of indicators, including:
- Inability to keep balance while listening to directions
- Beginning the test before the instructions are finished
- Stopping to regain balance
- Failure to touch heel-to-toe
- Stepping off the line
- Using the arms for balance
- Making an improper turn
- Incorrect number of steps

The One-Leg Stand Test

The OLS test is also a divided attention test. The subject must stand with one foot six inches off the ground while counting aloud until instructed to stop by the officer after 30 seconds. The indicators for which the examiner is looking in this test are:
- Swaying while balancing
- Using arms to balance
- Hopping to maintain balance
- Putting down the foot

A Sobering Look

Although NHTSA's approval suggests a uniform model for testing and assessing drivers, local and regional preferences for other tests do still exist. Several examples of non-standardized field sobriety tests still in use today include:
- Finger-to-nose test
- Recitation of the alphabet or a portion of it
- Reverse counting
- Finger-count test
- Hand-pat test
- Coin-pickup

In addition, the validity of the standardized tests is dependent upon officers following the established, standardized procedures under ideal conditions. Some researchers have claimed that the tests are administered incorrectly over 90 percent of the time. And conditions in the field are often far from ideal because of precipitation, wind, light and other environmental factors. In addition, factors such as the age, weight and medical condition of the driver may affect the test results.

Drivers who have been arrested for DUI or DAI should contact a knowledgeable attorney who can assess whether field sobriety tests were correctly administered, as well as other aspects of a drunk driving arrest. If protocols were not followed, it may be possible to suppress the BAC results or even have the charges dismissed.

Article provided by Law Offices of Basil D. Beck, III
Visit us at www.bbecklaw.com