Early morning July 23, 2017 an officer with the Washington State Patrol observed a vehicle failing to maintain its lane. The events of the traffic stop are captured by this impressively-low-quality video, so instead of giving the story away, this is a reasonable time to talk about the cues of impairment police officers look for in drivers. According to the NHTSA, the probability of detecting DWI by random traffic enforcement stops at night has been found to be about 3 percent, but research has identified certain cues of impairment that work with impressive accuracy. The NTSHA began its research into impairment cues by interviewing police officers from across the country. From those interviews they developed a list of more than 100 driving cues that were believed to be associated with blood alcohol concentrations ("BAC") of 0.08 percent or greater. The list was reduced to 24 cues during three subsequent field studies involving hundreds of officers and more than 12,000 enforcement stops. The driving behaviors identified fit into four categories: problems in maintaining proper lane position, speed and braking problems, vigilance problems, and judgment problems. The cues predict that a driver is DWI at least 35 percent of the time, and some cues, such as swerving, accelerating for no reason, and driving on other than the designated roadway, have single-cue probabilities greater than 70 percent. Generally, the probability of DWI increases substantially when a driver exhibits more than one of the cues. In many jurisdictions, departmental policy dictates all drivers stopped on suspicion of DWI be instructed to exit their vehicle. It’s important to note that by instructing the driver to exit their vehicle, the officer is not committing to an arrest. Rather, the instruction is another step in the DWI detection process, as the officer observes the manner in which the driver exits and notes any additional signs of impairment. There are many subtle cues the officer is looking for even prior to that point. For example, you will typically hear officers ask a driver for their license and registration. When the driver responds, officers are looking to see if the driver forgets one of the documents, produces the wrong document(s), fails to notice their license or registration, fumbles while handling either, or demonstrates an inability to retrieve the documents using their fingertips. Officers will frequently interrupt the driver's search for their license and registration with one or more simple questions, such as "Where are you coming from?" or "What day is it?" Possible evidence of impairment may be disclosed by the actions of the driver who ignores the question and concentrates only on the license or registration search, forgets to resume their search after answering the question, or supplies a grossly incorrect answer to the question. Impaired drivers will also often answer the wrong - expected -- question, for example providing their first name when asked for their middle name. Next time around: field sobriety testing. ~~~ Real World Police is proud to be a Sunshine Supporter of the Washington Coalition for Open Government — working to educate, advocate, and litigate the public's right to know. Want to know more about access to public records in Washington? Visit www.washingtoncog.org. ~~~ Do you have independently verifiable inside information on a story we are or should be covering? Email tips@realworldpolice.com. Your identity will not be revealed without your consent. Because we receive dozens of tips daily we cannot respond individually to every submission. If we need more information from you someone will be in touch. Remember: we don't publish footage that has already been published. Please don’t send links to news articles. ~~~ Follow us on Twitter @realworldpolice ~~~ Want to help make Real World Police happen and get rewarded for it? Become a supporter on Patreon today! Supporters get access to: -Exclusive full-length Real World Police videos -The Roadcam series -Supporting documentation: police reports, court records, and other investigatory material -Material from cases not shown on the main channel, like the arrest of Chris Hansen and the detention of T-Pain that time he accidentally tried to bring a gun through airport security -Early access to some videos -And more! https://patreon.com/realworldpolice Rather not? That works too. There are more than 490 free videos to enjoy!