50 to 75 percent | Problems Maintaining Proper Lane Position |
| Weaving |
| Weaving across lane lines |
| Straddling a lane line |
| Swerving |
| Turning with a wide radius |
| Drifting |
| Almost striking a vehicle or other object |
45 to 70 percent | Speed and Braking Problems |
| Stopping problems (too far, too short, or too jerky) |
| Accelerating or decelerating for no apparent reason |
| Varying speed |
| Slow speed (More than 10 miles mph under the limit) |
55 to 65 percent | Vigilance Problems |
| Driving in opposing lanes or wrong way on one-way |
| Slow response to traffic signals |
| Slow or failure to respone to officer’s signals |
| Stopping in lane for no apparent reason |
| Driving without headlights at night |
| Failure to signal or signal inconsistent with action |
| |
35 to 90 percent | Judgement Problems |
| Following too closely |
| Improper or unsafe lane change |
| Illegal or improper turn (too fast, jerky, sharp, etc.) |
| Driving on other than the designated roadway |
| Stopping inappropriately in response to officer |
| Inappropriate or unusual behavior (throwing, arguing, etc.) |
| Appearing to be impaired |
| |
Greater than 85 percent | Post Stop Clues |
| Difficulty with motor vehicle controls |
| Difficulty exiting the vehicle |
| Fumbling with driver’s license or registration |
| Repeating questions or comments |
| Swaying, unsteady or balance problems |
| Leaning on the vehicle or other object |
| Slurred speech |
| Slow to respond to officer or officer must repeat |
| Providing incorrect information, changes answers |
| Odor of alcoholic beverage from the driver |
| |
Greater than 50 percent when combined with any other clue: | Driving with no headlights at night |
| Failure to signal or signal inconsistent with action |