Friday, February 8, 2013

The Detection of DWI Motorcyclists - MN Motorcycle Safety Center

There are approximately eight and a half million street-legal motorcycles registered in the United States. Each year, one out of every 35 of those motorcycles is involved in a reported crash, and one out of every 1,200 or so is involved in a fatal crash. When fatalities per miles traveled are considered, motorcyclists are killed at about 19 times the rate of drivers and passengers of other motor vehicles. The National Highway Traffic Safety Administration (NHTSA) data shows that in 2003, 41 percent of motorcycle rider (and passenger) fatalities involved alcohol. In Minnesota in 2003, 62 people were killed in motorcycle crashes. Of the 46 motorcycle operators tested in these fatal crashes, 19 (41 percent) tested positive for alcohol use--13 were over the legal limit BAC.

The Motorcycle Rider - Safety Tips
There are some major differences between motorcycle riders and the drivers of other motor vehicles. Motorcyclists need more skill with the vehicle controls than car drivers. Motorcycles must constantly be balanced, and both hands, feet, and thumbs are continually in use operating the bike.

Motorcyclists must divide their attention between the bike and the road. Not only is the rider's whole body working just to operate the bike, riders must give maximum attention to road conditions and traffic. This can be very difficult for new riders still learning the controls. The biggest differences between cars and bikes:

  • Stability and vulnerability. 
  1.      Stability: Motorcycles only have two wheels, limited traction, and must constantly be balanced. 
  2.      Vulnerability: Riders do not have the benefit of a seat belt, air bags, or protective steel cage that drivers of other vehicles have.
  • Motorcyclists generally accept a higher level of risk. Given the differences between motorcycles and cars, motorcyclists are generally bigger risk takers than other drivers-- or completely ignorant of the risks.
  • Age and social factors may contribute to motorcycle crashes. It is possible that older drivers (35 years old and greater) may not take impaired driving as seriously as their younger counterparts. Many older riders grew up in a time when impaired driving and riding was not the "taboo" that it is today. Also, motorcycling in Minnesota and many other states is primarily a recreational activity, as is drinking alcohol. 
  • Riders use their motorcycles for fun, on weekends, with their friends, in the same way that they may use alcohol. 
  • Finally, given the nature of riders being more risk takers, motorcyclists may be more likely to be active drinkers, as well. 
    All these factors may add up to increase the likelihood that a motorcyclist will ride after drinking alcohol. Most riders feel that other drivers are their biggest risk. Motorcyclists almost unanimously claim that it's the "other guy" who is their biggest risk of crashing. They are wrong--dead wrong. Only about half of all motorcycle crashes involve another moving vehicle.

    The Problem of Impaired Riding
    Alcohol involvement in fatal motorcycle crashes is generally greater than that of fatal crashes among other vehicles. The risk of a fatal crash on a motorcycle increases dramatically as alcohol use increases.

    Risk of a Fatal Crash:

    • .05 - .09 BAC 11 times greater
    • .10 - .14 BAC 48 times greater
    • .15+ BAC 380 times greater

    In the last several years in Minnesota, the rate of fatal alcohol involvement for motorcyclists has ranged from 31 - 57 percent, but is generally about 45 percent--about 1/3 higher than for drivers of other vehicles. Midwestern states in general tend to have a higher-than average rate of fatal alcohol involvement for motorcyclists. Recently, 13 of 19 riders killed in Minnesota who tested positive for alcohol use had BACs of .10 or greater. 12 of these riders were 30-49 years of age.

    A. Excellent Cues (50+ percent probability)
    The special coordination and balance required to ride a motorcycle are the basis for these cues.

    Drifting During Turn or Curve
    Earlier studies have shown that the most comon cause of single-vehicle, fatal motorcycle crashes is for the road to curve and the motorcycle and rider to continue in a straight line until they strike a staionary object; this type of crsh is usually caused by alcohol-impaired balance and coordination abilities. In less extreme cases, the motorcycle's turn radius expands during the maneuver. The motorcycle appears to drift to the outside of the lane, or into another lane, through the curve or while turning a corner. If you see a motorcycle drifting during a turn or curve, do the rider a favor and pull him or her over--the study showed there is an excellent chance that he or she is DWI.

    1. The most common single-vehicle crash is the rider running wide in a turn and hitting a non-moving object.
    2. The operative word is "during" turn or curve. A proper motorcycle turn radius is one that increases towards the end of the curve. The Motorcycle Safety Foundation teachs and "outside-inside-outside" path of travel: The rider sets up for the turn on the outside edge of the lane, cuts across the inside of the lane in the middle (apex) of the turn, and finishes toward the outside of the lane. Even among sober motorcyclists, this technique is rarely perfect--but it is usually deliberate.
    3. Riders sometimes drift or swerve within their lane of travel to avoid road debris. Trouble with Dismount Parking and dismounting a motorcycle can be a helpful field sobriety test. the motorcyclist must turn off the engine, locate and deploy the kickstand. He or she must then balance their weight on one foot while swinging the other foot over the seat to dismount. But first, the operator must decide upon a safe place to stop the bike. Problems with any step in this sequence can be evidence of alcohol impairment.

    Late Braking During Turn
    The next turning problem is "late braking" during a turn or on a curve. A motorcyclist normally brakes prior to entering a turn or curve, so the motorcycle can accelerate through the maneuver for maximum control. An impaired motorcyclist might misjudge his or her speed or distance to the corner or curve, requiring them to apply the brakes during the maneuver.

    Note: Look for late braking that goes along with skidding the rear tire and/or the rider rinning wide in the turn.

    Improper Lean Angle During Turn
    A motorcyclist normally negotiates a turn or curve by leaning into the turn (i.e., leaning at the same angle as the motorcycle). However, when balance or speed judgment are impaired, the operator frequently attempts to sit upright through the maneuver. An "improper" lean angle can be detected by the trained observer.

    A vigilance problem is also evident when a motorcyclist is anattentive to his surroundings or seemingly unconcerned with detection. For example, there is cause for suspicion of DWI when a motorcyclist fails to periodically scan the area around his bike when in traffic, a wise defensive riding procedure to guard against potential encroachment by other vehicles. There is further evidence of impairment if a motorcyclist fails to respond to an officer's emergency lights or hand signals. If you observe a motorcyclist to be inattentive to his or her surroundings, there is an excellent chance that the motorcyclist is DWI.

    1. Most hazards approach riders from the front. Skilled riders pay far more attention to the area from 11:00 to 1:00 then their mirrors.
    2. Sometimes wind noise, exhaust noise, helmets, and earplugs can muffle the sound of a siren behind a motorcycle.

    Inappropriate or Unusual Behavior
    This category of cues includes behaviors such as operating a motorcycle while holding an object with one hand or under an arm, carring an open container of alcohol, dropping an item from a motorcycle, urinating or vomiting at the roadside, arguing with another motorist or otherwise being disorderly. If you observe inappropriate or unusual behavior by a motorcyclist, there is an excellent probablity that the motorcyclist is DWI.

    You are probably familiar with weaving as a predictor of DWI. If you seen an automobile weaving there is a good chance that the driver has exceeded the legal limits on alcohol, but if you observe a motorcycle to be weaving, the probability of DWI is even greater--weaving is an excellent cue. Weaving includes weaving within a lane and weaving across lane lines, but does not include the movements necessary to avoid road hazards.

    1. Riders generally have three positions (left, center, right) within the lane from which to choose. Expert  riders never stay in one position too long.
    2. Watch for more "drifting" or "meandering" paths of travel, rather than purposeful movements (position shifts for visibility), for DWI indicators.

    B. Good Cues (30-49 percent probability)
    These are cues that are good indicators of a rider's impairment level, but not as accurate as the excellent cues discussed so far. 

    Erratic Movements while Going Straight
    If you observe a motorcyclist making erratic movements while attempting to ride in a straight line, study results indicated there is a good probablity that the rider is DWI. In other words, during the study between 30 and 49 percent of the time erratic movements while going straight were observed in association with impaired operation.

    Note: Watch for sudden corrections to path of travel. Example: rider drifting toward the centerline or white stripe and suddenly "waking up" and correcting.

    Operating a motorcycle without lights at night is very dangerous and can indicate operator impairment. Study results showed that if you detect a motorcyclist riding at night without lights, there is a good chance that the operator is DWI.

    1. Most motorcycle headlights are on all the time, automatically.
    2. Some bikes have a headlight on/off switch; this is just one more thing for a rider to remember.
    3. A rider riding at night with no headlights is not very attuned to his or her bike or safety.

    Motorcyclists tend to ride faster than autos, so speeding is not necessarily a good predictor of DWI for motorcylists. However, recklessness, or riding too fast for the conditions, was found to be a good indicator of operator impairment.

    Following Too Closely
    Following too closely, an unsafe following distance, is an indication of impaired operator judgment. this cue was found during the study to be a good predictor of motorcycle DWI

    1. This cue is especially true when traffic is light and there's no need to tailgate.
    2. Note that the rider may be waiting for a safe opportunity to pass a slow-moving vehicle.

    Running a Stop Light or Stop Sign
    Failure to stop at a red light or stop sign can indicate either impaired vigilance  capabilities (i.e., did not see the stop light or sign--or officer), or impaired judgment (i.e., decided not to stop). Whatever the form of impairment, if you observed a motorcyclist to run a stop light or sign, there is a good chance that he or she is DWI.

    Evasion, or fleeing an officer, is a relatively frequent occurence. If a motorcyclist attempts to evade an officer's enforcement stop, study results indicate that there's a good chance he's DWI. Evasion is a good indicator that the rider is impaired: Poor judgment, increased risk taking, false bravado.

    Wrong Way
    Obviously, riding into opposing traffic is extremely dangerous. Study results showed that when you find a motorcycle going the worng way in traffic there is a good chance that the operator is under the influence. Thsi includes going the wrong way on a one-way street and crossing a center divider line to ride into opposing traffic.This is another example of impaired vigilance to the rider's surroundings. The rider may not even know they're going the wrong way!

    **Important Information**
    The cues described so far have been used by law enforcement officers from across the United States to help detect impaired motorcycle operators. The cues can be used at all hours of the day and night, and they apply to all two-wheeled motor vehicles. The cues described and illustrated so far are the behaviors that are most likely to discriminate between impaired and normal operation of a motorcycle. However, the special case of "speeding" requires elaboration.

    Motorcyclists stopped for excessive speed are likely to be DWI only about 10 percent of the time (i.e., ten times out of 100 stops for speeding). But because motorcyclists tend to travel in excess of speed limits, speeding is associated wtih a large portion of all motorcycle DWI arrests. In other words, while only a small proportion of speeding motorcylcists are liekly to be DWI, the large number of speeding motorcyclists results in a large number of DWIs, despite the relatively small probability.

    1. Sometimes new riders, when learning, ride dangerously slow, think that they are safer at a slower speed.
    2. Expert riders who want ot enjoy the scenery slow down so potential hazards don't come at them so fast and they can afford to sightsee a little without compromising as much of their safety.

    Skill Impairment at .03 and Greater BAC
    The final element to DWI detection of motorcycle riders is to better understand what critical riding skills are impaired by alcohol, and how these skills come into use in traffic environment. These next examples will show how riding skills are impaired as a rider rider moves up the ladder of blood alcohol concentration from zero to .10.

    Even on his or her best of days, riding is still a challenge for a sober, experienced rider. Riders make mistakes in traffic all the time. Alcohol compounds and intensifies those mistakes and is likely to bring about dire consequences for the impaired rider.

    Complex Reaction Time .03 BAC
    This is the amount of time it takes for the brain to process multiple environmental inputs and prepare and execute multiple responses, and is one of a rider's most critical skills. Motorcycle riders have to operate the bike and react to various hazards constantly. 
    • Example: A rider approaching a yellow light with an oncoming vehicle waiting to turn across his or her path. This is a triple hazard. 
              1) The oncoming vehicle could turn into the motorcyclist's path, 
              2) The motorcyclist has to decide whether to proceed through the light or to stop,
              3) A vehicle following the motorcycle has to make that same decision. 

    If the rider does not take all three factors into account and react to them all within a second or two, he or she may be in great danger. This critical skill is impaired by alcohol at a modest .03 BAC.

    Simple Reaction Time .03 BAC
    This is the amount of time it takes to process an environmental factor and prepare and execute a response. Even one risk factor can jeapordize a rider's safety. 
    • Example: A country road with deer lurking in the bushes at the roadside. A rider who fails to recognize the deer in the ditch in time may be in for a big spill. Riders faced with this situation often don't know whether to stop, swerve, or slow and then swerve. Doing both at once (stopping and swerving) can cause the bike to crash on its own. Also, if a rider decides to swerve, he or she must also choose a direction, remain on the road, and not cross into oncoming traffic. 
    • What seems simple enough when sober can be a big problem just at a .03 BAC.
    Tracking .05 BAC
    Tracking is monitoring the progress or movement of an object. Riders need to constantly judge other road users' speed and diretion. Expert riders can use peripheral vision to help track other road users while focusing on something else. 
    • Example: A motorcyclist is traveling and has the right of way while a car approaches from a side street. Imagine an impaired rider who doesn't realize the car approaching from the side is not slowing, but accelerating to try to beat the rider through the intersection, or the rider who doesn't realize that the dog that appears stationary is actually racing directly toward the rider, or that the train that appears stopped is actually moving. 
    • At .05 BAC, a rider's ability to track objects properly is compromised.
    Skilled Psychomotor Tasks .05 BAC
    This is your mind and body working together. For a motorcyclist, this is their mind's ability to tell the body what to do and how to do it--and for the body to react appropriately.
    • Example: A rider on a country road who realizes a turn is getting tighter uses skilled psychomotor tasks to slow down and/or steer harder in order to keep the bike on the road. A rider at a .05 BAC may not be able to react to simple changes in curve radius--such as a decreasing-radius turnon an off ramp.
    Oculomotor Control .05 BAC
    This is eye movement, scanning and focusing on the environment: near, far, mirrors, right side, left side, and instruments/gauges. Vision is a rider's primary source of information. Riders need to collect hundreds of bits of information every minute to evaluate their environment and adjust their speed and position accordingly.
    • Consider this example. Which rider would live longer in traffic: 
              1) A sober rider with 20/20 vision riding in traffic where every other driver was  blindfolded, or 
              2) A sober rider who is blindfolded riding in traffic where every other driver has perfect 20/20 vision? 
    • A rider's ocularmotor control is compromised at .05 BAC.
    Divided Attention .08 BAC
    To divide your attention is to focus on multiple tasks simultaneously. Keeping the bike balanced, keeping it between the lines, scanning the road surface and road signs, and watching other traffic are all required constantly on a motorcycle. At .08, a rider may have trouble doing everything at once, and spend too much time or attention on one thing (watching his or her speedometer, for example) while neglecting others (the light that just turned red, for example).

    Information Processing .08 BAC
    Environment, observation, perception, and decision. Riders must scan the environment and be aware of everything, observe those factors which are important, perceive how those factors can affect his or her safety, and make decisions to keep the motorcycle moving forward, upright, on two wheels.
    • Example: The "abandoned" car on the opposite shoulder is actually moving and about to do an illegal U-turn. Riders must constantly play the "What If?" game. Without accurate information processing, a rider cannot ride defensively or spot hazards before they become disasters. "Is the shiny patch on the road water? Coolant? Oil? An asphalt patch? Is the tree stump in the ditch actually a deer? Did that sign say there was a 50 mph corner or a 30 mph corner coming up?" 
    • At .08 BAC, a rider's ability to process vital information is severely compromised.
    Driving-Related Tasks .08 BAC
    These are the simple driving components such as throttle control, braking, turning, shifting, and signaling. When a rider is impaired, simple motorcycle controls like the throttle or brakes become difficult to use. An impaired rider may forget to check his or her blind spot before changing lanes. A rider may need to brake suddenly, accidentally lock up the rear brake, then release it suddenly, vaulting him or her into oncoming  traffic--or lock up the brakes and go down immediately.
    • Example: Approaching an intersection in which a car is waiting to pull out, the rider has accidentally left the turn signal blinking. Even the simplest thing like an unintended signal, in the eyes of someone in a hurry at an intersection, can have devastating consequences. Motorcycle turn signals usually must be turned off manually by the rider, unlike cars. It is common for riders to forget about them and not notice they're blinking even when they're sober.
    Concentrated Attention .09 to .10 BAC
    This means to focus on the task at hand. At .09 to .10, the rider is no longer even riding the bike; the bike is taking him or her for a ride.
    • Examples: A rider is looking over at the inner tubers floating down the river in their swimsuits, or staring at a beautifully restored Chevell SS in the lane next to them, or starting to feel cold and zipping up their jacket, or trying to open another beer without leaving the roadway.
    Skill Impairment .09 to .10 BAC
    Meaningful interpretation of the environment is impaired at .09 to .10 BAC. At this stage, the rider may not be able to tell that a curving road that looks paved is actually loose gravel. A rider may not be albe to tell good pavement from bad pavement or wet pavement from dry pavement. A rider may believe that a moving, occupied vehicle is actually a stationary, unoccupied one. A rider may think he or she is more skilled than they actually are. A rider may think the ladies in the car next to him are gawking at him because he looks so cool and dangerous, while in reality, they're amazed that the crazy motorcycle guy is about to run through a constrution barrier and over a cliff like Wile E. Coyote!

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