Driving While Intoxicated Reasonable Suspicion to stop
DWI Reasonable Suspicion to stop
There are several situations in which the officer will come into contact with a driver, some examples are:
- The driver has been involved in an automobile accident; the officer has responded to the scene and is conducting an investigation.
- The driver has been stopped at a sobriety checkpoint (also known as roadblocks).
- The police have received a report, possibly from an anonymous citizen, that a described car has been driving erratically. The officer should verify the erratic driving before pulling the driver over. In some cases, the driver will no longer be in the vehicle.
- The officer on patrol has observed erratic, suspicious driving, or a series of traffic infractions indicating the possibility that the driver may be impaired. This is by far the most common reason for stopping a suspect.
- A police officer has stopped a vehicle for a lesser traffic offense, notices the signs of intoxication, and begins the DUI investigation.
The following list of DUI symptoms, from a publication issued by the National Highway Traffic Safety Administration (DOT HS-805-711),[5] is widely used in training officers to detect drunk drivers. After each symptom is a percentage figure which, according to NHTSA, indicates the statistical chances through research, that a driver is over the legal limit.
| Turning with wide radius | 65 |
| Straddling center or lane marker | 65 |
| Appearing to be drunk | 60 |
| Almost striking object or vehicle | 60 |
| Weaving | 60 |
| Driving on other than designated roadway | 55 |
| Swerving | 55 |
| Slow speed (more than 10mph below limit) | 50 |
| Stopping (without cause) in traffic lane | 50 |
| Drifting | 50 |
| Following too closely | 45 |
| Tires on center or land marker | 45 |
| Braking erratically | 45 |
| Driving into opposing or crossing traffic | 45 |
| Signaling inconsistent with driving actions | 40 |
| Stopping inappropriately (other than in lane) | 35 |
| Turning abruptly or illegally | 35 |
| Accelerating or decelerating rapidly | 30 |
| Headlights off | 30 |
If the officer observes enough to have a reasonable suspicion to legally justify a further detention and investigation, he will ask the driver to step out of the vehi