‘Ever wonder just what the police are looking for when they’re out at night looking for drunk drivers?  And how you can avoid looking like one?

The following list of DUI driving symptoms, from a publication issued by the National Highway Traffic Safety Administration (DOT HS-805-711), is widely used in training officers to detect drunk drivers on the roads.  After each symptom is a percentage figure which, according to NHTSA, indicates the chances that a driver is under the influence of alcohol.  For example, NHTSA’s research indicates that “the chances are 65 out of 100″ that a driver who is straddling a center or lane marker has a blood-alcohol concentration of .10% or higher (the pre-.08% standard).

Turning with wide radius     65
Straddling center or lane marker     65
Appearing to be drunk     60
Almost striking object or vehicle     60
Weaving     60
Driving on other than designated roadway     55
Swerving     55
Slow speed (more than 10mph below limit)     50
Stopping (without cause) in traffic lane     50
Drifting     50
Following too closely     45
Tires on center or land marker     45
Braking erratically     45
Driving into opposing or crossing traffic     45
Signalling inconsistent with driving actions     40
Stopping inappropriately (other than in lane)     35
Turning abruptly or illegally     35
Accelerating or decelerating rapidly     30
Headlights off     30

Just to reenforce this as a mathematical science thoroughly impressive to juries, NHTSA further claims — and officers are taught — that there is also a quick-and-easy formula for multiple symptoms:  “When two or more cues are seen, add 10 to the highest value among the cues observed”.

Of course, if these suspiciously precise figures are to be believed, then almost half of the folks who tailgate you every day are drunk – and almost half of the time you don’t brake smoothly you are, too.  Further, only 60% of drivers “appearing to be drunk” to the officer actually are. (Query:  How does a driver “appear to be drunk” to an officer following 100 feet behind? Slurred speech?  Alcohol on his breath?)  And speeding — one of the most common reasons for pulling DUI suspects over — is not even on the list. 

Science marches on…