Alcohol intoxication is a leading factor in motorcycle accidents and fatalities. Law enforcement officers have been trained to identify driving patterns that indicate a probability that a motorcyclist is driving while intoxicated. The driving patterns that police typically look for have been outlined by the National Highway Traffic and Safety Administration (NHTSA). NHTSA has delineated a number of "cues" that police officers can look for in detecting intoxicated motorcyclists. The list presented below represents, in descending order, the visual cues giving rise to the probability that the motorcyclist observed is driving while intoxicated. Often, police officers will observe several cues in conjunction, which increases the probability that the driver is intoxicated, that is, driving with a blood alcohol content (BAC), over the legal limit. Studies have indicated that cues by themselves or in conjunction with other cues, give rise to a statistical probability of intoxication.
The following cues have shown a 50 percent or greater probability in predicting impaired motorcycle operation. However, it is also 50 percent as likely that these cues do not reflect intoxication.
Drifting During Turn or Curve
Drifting during a turn or curve is the most common cause of single vehicle, motorcycle crashes. This occurs when the motorcycle and rider continues in a straight line instead of turning with the road, ultimately resulting in hitting a stationary object.
Another way this cue represents itself is where the motorcycle appears to drift to the outside of the lane, or into another lane, through the curve or while turning a corner.
However, drifting in a lane is not uncommon where a person is distracted or is unfamiliar with the landscape.
Trouble with Dismount
Law enforcement officers look at the dismount as a helpful field sobriety test, as it is reflective of coordination and judgment. First, the motorcyclist must decide upon a safe place to stop the bike. Then the motorcyclist must turn off the engine, locate and deploy the kickstand, then balance on one foot while swinging the other foot over the seat to dismount. Officers look for any problems in the preceding sequence as evidence of alcohol impairment.
However, trouble with dismount is not necessarily an indication of intoxication. Where the officer pulls over the motorcyclist has a lot to do with the location of dismount. Plus, most people are rather nervous when pulled over, which is distracting. These factors have a lot to do with a dismount that takes place in front of an officer while he is waiting to write you a ticket.
Trouble with Balance at Stop
There are two general methods of balancing at a complete stop. One, where the rider places one foot on the ground to keep the bike upright, while leaving the other foot on the peg nearest the gear shift lever. Two, where the rider places both feet on the ground for stability. Law enforcement officers look for a shifting from side to side, in a rocking motion, in an effort to maintain balance at a stop.
However, there may be several reasons a rider cannot maintain balance, for example, if the road is not even, the bike is unfamiliar, or the rider is of small stature
Turning Problems
1) Unsteady During Turn or Curve: Law enforcement officers look for a motorcycles wheels to wobble when making a turn.
However, when the motorcycle is undergoing a turn or curve, it must slow down, which makes it less stable in an upright position. At higher speeds the gyroscopic effects of a motorcycle's wheels tend to keep the motorcycle "on track" so long as the speed is maintained. At slower speeds, the motorcycle is unsteady, so there is a higher probability of wobbling while turning.
2) Late Breaking During a Turn: Law enforcement officers look for the application of break lights during the turn as opposed to prior to the turn, as indicating impairment due to intoxication. The rationale here is that a motorcyclist normally breaks prior to entering a turn or curve, so the motorcycle can accelerate through the maneuver for maximum control.
However, there are many reasons a rider would break during a turn as opposed to prior. For example, the rider may just drive that way, or is unfamiliar with the streets and the street he needs to turn on comes up faster than expected, or any number of reasons, which are not alcohol-related.
3) Improper Lean During Turn: Law enforcement officers look for the rider to be in an upright position during a turn, instead of leaning into the curve.
However, NHTSA indicates that this cue is observable by a "trained" observer, meaning it is not apparent otherwise. Also, where the turn is made safely, there is no indication of impairment due to intoxication.
4) Erratic Movements During Turn: Law enforcement officers look for any sudden correction of a motorcycle during a turn or curve.
However, there are many other factors which would cause a sudden movement during a turn. For example, the condition of the road may necessitate such a maneuver.
Inattentive to Surroundings
Law enforcement officers look for such things as:
1) Failing to notice the light has changed. However, people do this everyday. Getting lost in thought may cause you to not notice that the light has changed: This is not an indication of intoxication.
2) Failing to scan the area around the bike in traffic. However, this is not a requirement required by the DMV and is not necessary where the driver is experienced and the traffic is light. The motorcyclist decides based on road factors, traffic flow, and surroundings how vigilant to be; it is subjective and not an indication of intoxication.
3) Failing to respond to officer's emergency lights or hand signals. However, this cue can be negated by many reasonable factors, like the motorcyclist concentrating on the road, waiting to pull over on a safer stretch of road, or simply not observing the hand signals.
Inappropriate or Unusual Behavior
Officers are looking for any sorts of behavior which are "unusual" or "inappropriate."
However, this is a matter of subjection and is not necessarily an indicator of intoxication, but matters of circumstance.
Weaving
Weaving includes weaving within a lane and weaving across lane lines.
However, weaving may occur to avoid road hazards.
The following cues have been shown to have a 30-50% probability of indicating intoxication. However, at the same time, they are 50-70% times as likely of not being an indicator of intoxication.
Erratic Movements While Going Straight
Law enforcement officers look for any sudden corrections while attempting to ride in a straight line.
However, the NHTSA studied reflected a 51-70% probability that there is no impairment reflected in this cue.
Operating without Lights at Night
Because of the danger involved in motorcycles driving without lights at night, the NHTSA studies indicated that there is a good chance that the operator is intoxicated.
However, there is a higher likelihood that this cue is not due to intoxication, but rather just an oversight of the rider.
Recklessness
Officers look for riding too fast as an indicator of impairment.
However, motorcyclists tend to ride faster than autos, so speeding is not necessarily an indicator of impairment.
Following too Closely
Officers look for a rider following at an unsafe following distance.
However, the distance between the motorcycle and other cars is not totally within the motorcyclist's control. Cars slowing would naturally decrease the following distance.
Running Stop Light or Sign
Officers look for the motorcycle failing to stop at a light or sign.
However, cars and motorcycle riders run lights and signs all the time, for a variety of reasons which are not indicators of intoxication.
Evasion
This cue occurs when an officer attempts to pull the motorcycle over and the motorcycle rider attempts to flee the officer instead.
This is a common occurrence which has nothing to do with impairment, 50-70% of the time.
Wrong Way
This cue occurs when the motorcycle is riding into opposing traffic, such as going the wrong way on a one-way street or crossing a center divider line to ride into opposing traffic.
However, 50-70% of the time this cue is not an indicator of impairment. Going the wrong way on a one-way street occurs with drivers everyday and is usually a matter of mistake. Crossing the divider line also occurs as a sudden movement to avoid another car going into the lane which occurs frequently to motorcycles because other driver's do not pay attention to the presence of motorcycles.
DUI and Motorcycles:Darren Kavinoky