Written by attorney Jonathan Neal Portner

What an officer considers before stopping a motorcycle for DWI/DUI - Part II

Drifting During Turn or Curve

A motorcycle is drifting when it “appears to drift to the outside of the lane or into another lane, through the curve or while turning a corner." While riding a motorcycle, the “cornering line" is the line providing the best sight-line and traction. The “cornering line" is found at the outside of the rider’s lane. From a Columbia, Maryland police officer’s point-of-view, a bike cornering correctly will have drifted to the outside of its lane, then to the inside of the lane, and back outside again. Thus, proper cornering technique may be construed as a predictor of DWI.

Trouble with Dismount

In order to properly dismount, a motorcyclist must turn off the engine and then find and deploy the kick-stand. Usually, when dismounting, a motorcyclist will shift his weight onto one foot while bringing the other foot over the seat. This maneuver is more difficult when the rider is using a center-stand as it requires the rider to balance the weight of the motorcycle while deploying the stand and then lift the bike backwards onto the stand. If a police officer were to witness any problems with any step of the dismount, it can be evidence of alcohol impairment. It should be noted that in the past 10 years, men who are 40-49 years old bought more motorcycles than any other age group. It is also this same demographic that makes up the majority of persons charged with DWI on a motorcycle. What is interesting is that many in this age group already suffer with physical issues which may impair their ability to flawlessly perform the delicate balancing act of dismounting a motorcycle. To compound the problem, this age bracket also purchases the largest motorcycles, many averaging a weight of 800 to 900 pounds. If a rider is aging, a novice, or returning after many years away from riding, the weight of such a heavy vehicle may be too difficult to manage and balance.

Trouble with Balance at a Stop

To make a stop on a motorcycle, the typical practice is for a motorcyclist to place one foot on the ground to keep the bike upright while leaving the other foot on the peg nearest the gear shift lever. If a motorcyclist is seen “having trouble with balance at a stop, there is an excellent chance that he or she is DWI." This means that police officers are taught that a rider is impaired by alcohol if he is seen shifting his weight from foot to foot to maintain balance. The trouble is that some riders prefer to place both feet on the ground for stability, which may be mistakenly interpreted as being DWI.

Turning Problems

Four examples are used to describe “turning problems:"

  1. Unsteadiness: Unsteadiness, also known as a “wobble" in the front handlebars or front wheel, is said to be an indicator of turning problems. The term “wobble" or “wobble in a turn" is frequently used in motorcycle literature to describe a common occurrence when there is a change in weight distribution, tire pressure, accessory, or mechanical issue. Thus, wobbling on a motorcycle may not mean that a motorcyclist is DWI, but managing changes in the motorcycle.

  2. Late Braking in a Curve or Turn: A motorcyclist will usually brake prior to entering a curve and accelerate coming out a curve, but the brochure states that “an impaired motorcyclist might misjudge his speed or distance to the corner or curve, requiring him to apply the brakes during the maneuver." Part of riding a motorcycle is that when quickly entering a curve or finding the radius decreasing more than one initially expected, one handles this problem by increasing counter-steering pressure and lean angle. Usually, when a rider applies brakes in a curve, it leads to an unwanted dismount unless the rider has room to bring the bike to an upright position and brake hard. Thus, an officer will rarely find a motorcyclist who is able to actually apply brakes during a curve or turn without extreme skill and luck.

  3. Improper Lean Angle During Turn: When asking a police officer to determine improper lean, it is assuming that Howard County street officers understand the proper lean angles for motorcycles in curves and turns of various radii. The best turn-in, apex, and exit line for a curve allows the motorcycle to remain as upright as possible. The advantages of being as upright as possible in a curve are the additional traction it provides, should braking be necessary, and the additional room to lean if the curve radius decreases unexpectedly. This means that choosing to be as upright as possible, and not fulling leaning on each turn, could be deemed a cue for impairment by police officers, even though that this is the proper way in which a motorcycle should be handled.

  4. Erratic Movements During a Turn: “An erratic movement or sudden correction of a motorcycle during a turn or curve can also indicate impaired operator ability." Riders often must make adjustments while riding when sight-lines are limited, or when there are obstacles on the road that must be avoided. Motorcyclists must be wary of factors that car drivers do not consider, such as gravel on the road, vehicles getting too close to the center line, vehicles inching forward onto the street, or even dogs along the roadway. All of these can contribute to a rider making “sudden corrections."

Inattentive to Surroundings

While riding a motorcycle, the rider must be aware of his surroundings at all times. Despite this, it is very difficult for a police officer to detect whether a motorcyclist is actually attentive to his surroundings or not. The movements of a motorcyclist’s head is not a reliable indicator as to how aware a rider is to his surroundings because the head movements of a motorcyclist changes depending on traffic conditions and situational circumstances.

Inappropriate or Unusual Behavior

Listed examples of inappropriate behaviors include riding with an object under an arm, carrying an open container of alcohol, dropping an item from the motorcycle, urinating at the roadside, arguing with another motorist, or otherwise being disorderly. The brochure also gives police officers leeway to use any sort of observation that the officer finds to be inappropriate or unusual as a basis for stopping a motorcyclist. This anything-goes cue is an invitation for police officers to find any reason to pull a motorcyclist over.


The brochure teaches that “weaving" includes “weaving within a lane and weaving across lane lines, but does not include movements necessary to avoid road hazards." Depending on the surroundings, experienced motorcyclists may shift lane positions frequently and will also not ride along the center of the roadway. Debris from car and truck tires are deposited on the side of the lane or in the middle. Furthermore, oil and gasoline drippings drop in the middle of the lane. In order to avoid these obstacles, a motorcyclist will ride along the tire tracks to the left or to the right of the lane. When choosing between the left or right tire track, a motorcyclist has to look at the conditions of the road and will often change between the left and the right depending on the road situation. Thus, a motorcyclist properly avoiding obstacles can be seen as a cue of DWI.

Defense in Motorcycle DWI Cases

The experienced Bethesda, Maryland DUI/DWI defense attorneys at Portner & Shure know that Montgomery County, Maryland police officers may not fully understand the maneuvers and mechanics of riding a motorcycle unless they themselves actually ride a motorcycle. As we have reviewed, even proper maneuvers can easily be misinterpreted by a Howard County, Maryland police officer to be an “excellent predictor" of intoxication. The knowledgeable Columbia, Maryland DUI/DWI defense lawyers at Portner & Shure know that it is difficult for police officers to actually determine whether a motorcyclist is intoxicated or not.

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