{"id":7629,"date":"2024-12-17T09:43:57","date_gmt":"2024-12-16T22:43:57","guid":{"rendered":"https:\/\/www.optalert.com\/?p=7629"},"modified":"2026-09-21T15:04:45","modified_gmt":"2026-09-21T05:04:45","slug":"dms-por-vision-detecta-deterioro-no-bac","status":"publish","type":"post","link":"https:\/\/www.optalert.com\/es\/vision-based-dms-can-only-detect-impairment-not-bac\/","title":{"rendered":"Los DMS basados en visi\u00f3n solo pueden detectar el deterioro, no la BAC"},"content":{"rendered":"\t\t
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In the final post in our three-part series about alcohol impairment, we argue that vision-based driver monitoring systems (DMSs) can accurately detect driver impairment, but not BAC.\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/div>\n\t\t\t\t\t<\/div>\n\t\t<\/section>\n\t\t\t\t

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Blood alcohol concentration (BAC) is the prevailing metric to classify a driver as unfit to drive. However, our research shows that impairment persists long after BAC declines, as outlined in the first article in this series<\/a>. When we say \u201cimpairment\u201d, we refer to the increased likelihood of a person making a mistake while driving by not reacting when they should.<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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Figure 1. On average, participants\u2019 impairment peaks 3.5 hours after their BAC peaks. In summary, BAC is a leading indicator that results in impairment for hours to come. <\/figcaption>\n\t\t\t\t\t\t\t\t\t\t<\/figure>\n\t\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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On the back of our research to understand how impairment arises after an elevated BAC, we also developed an eyelid-based model to detect this impairment, which is covered in greater detail in the second article in this series<\/a>. In the process of developing this model, our data scientists investigated whether visual inputs could also predict a person\u2019s BAC.\u00a0<\/p>

Unsurprisingly to our team, visual inputs were much better at measuring impairment than BAC. But what continues to surprise us is how many engineering teams are still attempting to build algorithms within a vision-based DMS using BAC as the ground truth. And they repeatedly struggle to achieve good performance as a result.\u00a0<\/p>

This article clarifies why a vision-based DMS is best suited to detecting impairment, but will never achieve high accuracy at measuring BAC.\u00a0<\/p>\t\t\t\t\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t

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A summary of our study on intoxication<\/h2>\t\t\t\t<\/div>\n\t\t\t\t<\/div>\n\t\t\t\t
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Working with the team from KEA Technologies in Boston, we conducted a comprehensive study on how impairment develops after alcohol consumption. The BAC and psychomotor impairment of 30 diverse participants were monitored over a 5 to 8-hour period after drinking alcohol. We found that while BAC peaks early and decreases linearly afterwards, impairment continues to increase for hours. In other words, drivers can be severely impaired for hours even when under the legal limit for BAC.\u00a0<\/p>

To develop our model, we needed visual data of the participants as they performed the vigilance tests. They were recorded using two cameras in the following locations:<\/p>