Explanations of the 24 driving cues Problems in Maintaining Proper Lane Position Speed and Breaking Problems Vigilance Problems Judgement Problems Table of Contents

Problems in Maintaining Proper Lane Position Maintaining proper lane position can be a difficult task for an impaired driver. For example, we have all seen vehicles weaving before. Weaving is when the vehicle alternately moves toward one side of the lane and then the other. The pattern of lateral movement can be fairly regular, as one steering correction is closely followed by another. In extreme cases, the vehicle's wheels even cross the lane lines before a correction is made. You might even observe a vehicle straddling a center or lane line. That is, the vehicle is moving straight ahead with either the right or left tires on the wrong side of the lane line or markers. Weaving Drifting is when a vehicle is moving in a generally straight line, but at a slight angle to the lane. The driver might correct his or her course as the vehicle approaches a lane line or other boundary, or fail to correct until after a boundary has been crossed. In extreme cases, the driver fails to correct in time to avoid a collision. Drifting Course corrections can be gradual or abrupt. For example, you might observe a vehicle to swerve, making an abrupt turn away from a generally straight course, when a driver realizes that he or she has drifted out of proper lane position, or to avoid a previously-unnoticed hazard. Swerving A related DWI cue is almost striking a vehicle or other object. You might observe a vehicle, either at slow speeds or moving with traffic, to pass unusually close to a sign, barrier, building, or other object. This cue also includes almost striking another vehicle, either moving or parked, and causing another vehicle to maneuver to avoid a collision. Turning with a wide radius, or drifting during a curve, is the final cue in this category of driver behaviors. A vehicle appears to drift to the outside of the lane, or into another lane, through the curve or while turning a corner. Watch for this cue and stop the driver when you see it. Many alcohol-involved crashes are caused by an expanding turn radius, or drifting out of lane position during a curve. Turning with a Wide Radius Back to Top

Speed and Braking Problems The research showed that braking properly can be a difficult task for an impaired driver. For example, there is a good chance the driver is DWI if you observe any type of stopping problem. Stopping problems include, Stopping too far from a curb or at an inappropriate angle, Stopping too short or beyond a limit line, and Jerky or abrupt stops. Stopping Beyond a Limit Line Impaired drivers also can experience difficulty maintaining an appropriate speed. There is a good chance the driver is DWI if you observe a vehicle to, Accelerate or decelerate rapidly for no apparent reason, Vary its speed, alternating between speeding up and slowing down, or be Driven at a speed that is ten miles per hour or more under the limit. Back to Top

Vigilance Problems Vigilance concerns a person's ability to pay attention to a task or notice changes in surroundings. A driver whose vigilance has been impaired by alcohol might forget to turn his or her headlights on when required. Similarly, impaired drivers often forget to signal a turn or lane change, or their signal is inconsistent with their maneuver, for example, signaling left, but turning right. Signaling Inconsistent with Driving Actions Alcohol-impaired vigilance also results in motorists driving into opposing or crossing traffic, and turning in front of oncoming vehicles with insufficient headway. Driving into Opposing or Crossing Traffic Driving is a complex task that requires accurate information about surrounding traffic conditions. Failing to yield the right of way and driving the wrong way on a one way street are dangerous examples of vigilance problems. A driver whose vigilance has been impaired by alcohol also might respond more slowly than normal to a change in a traffic signal. For example, the vehicle might remain stopped for an unusually long period of time after the signal has turned green. Similarly, an impaired driver might be unusually slow to respond to an officer's lights, siren, or hand signals. The most extreme DWI cue in the category of vigilance problems is to find a vehicle stopped in a lane for no apparent reason. Sometimes when you observe this behavior the driver will be just lost or confused, but more than half of the time the driver will be DWI-maybe even asleep at the wheel. Back to Top

Judgment Problems Operating a motor vehicle requires continuous decision-making by the driver. Unfortunately, judgment abilities can be affected by even small amounts of alcohol. For example, alcohol-impaired judgment can cause a driver to follow another vehicle too closely, providing an unsafe stopping distance. Alcohol-impaired judgment also can result in a driver taking risks or endangering others. If you observe a vehicle to make improper or unsafe lane changes, either frequently or abruptly, or with apparent disregard for other vehicles, there is a good chance the driver's judgment has been impaired by alcohol. Similarly, impaired judgment can cause a driver to turn improperly. For example, misjudgments about speed and the roadway can cause a driver to take a turn too fast, or to make sudden corrections during the maneuver. These corrections can appear to the observer as jerky or sharp vehicle movements during the turn. Alcohol-impaired judgment can affect the full range of driver behaviors. For example, the research found that impaired drivers are less inhibited about making illegal turns than unimpaired drivers. Turning Illegally Driving on other than the designated roadway is another cue exhibited by alcohol-impaired drivers. Examples include driving at the edge of the roadway, on the shoulder, off the roadway entirely, and straight through turn-only lanes. In some cases, impaired drivers stop inappropriately in response to an officer, either abruptly as if they had been startled, or in an illegal or dangerous manner. In fact, the research has shown that there is a good chance a driver is DWI if you observe the person to exhibit any inappropriate or unusual behavior. Unusual behavior includes throwing something from the vehicle, drinking in the vehicle, urinating at the roadside, arguing with another motorist, or otherwise being disorderly. If you observe inappropriate or unusual behavior, there is a good probability that the driver is DWI. Driving on Other than the Designated Roadway The final cue is actually one or more of a set of indicators related to the personal behavior or appearance of a driver. These indicators include, gripping the steering wheel tightly, driving with one's face close to the windshield, slouching in the seat, and staring straight ahead with eyes fixed. Some officers routinely scrutinize the faces of drivers in oncoming traffic, looking for the indicators of impairment. If you observe a driver who appears to be impaired, the research showed that there is an excellent probability that you are correct in your judgment. Appearing to be Impaired Back to Top