{"id":574406,"date":"2026-05-16T10:00:57","date_gmt":"2026-05-16T14:00:57","guid":{"rendered":"https:\/\/www.dannygloverlawfirm.com\/blog\/?p=574406"},"modified":"2026-05-07T09:47:00","modified_gmt":"2026-05-07T13:47:00","slug":"dui-eye-test-hgn","status":"publish","type":"post","link":"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/","title":{"rendered":"The DUI Eye Test (HGN) | What It Measures and How Reliable It Really Is"},"content":{"rendered":"<p>The &#8220;DUI eye test&#8221; refers to the <strong>Horizontal Gaze Nystagmus<\/strong>, or &#8220;<strong>HGN<\/strong>.&#8221; It is one of the three &#8220;verified&#8221; Standardized Field Sobriety Tests (SFSTs) recognized by the National Highway Traffic Safety Administration (NHTSA), along with the walk-and-turn and the one-leg stand.<\/p>\n<p>HGN is a &#8220;sobriety test&#8221; where an officer holds a stimulus, usually a pen, a fingertip, or a small flashlight, in front of the suspect&#8217;s face and asks the driver to follow it with their eyes without moving their head. The officer is watching for an involuntary jerking or twitching of the eyes. Some officers describe it as looking like windshield wipers going back and forth on a dry windshield. That jerking motion is referred to as a nystagmus and it is purportedly an indicator of appreciable impairment by alcohol and possibly other substances.<\/p>\n<p>The test sounds simple. The science behind it is not. Whether HGN is actually a reliable indicator of impairment in any given case is a separate question. Even when scientifically reliable, the accuracy and reliability of field sobriety testing largely depend on the training, experience, and objectivity of the charging officer.\u00a0 That\u00a0matters when the test results are summarized in a police report, described on the witness stand, or used to support probable cause for arrest under North Carolina&#8217;s impaired driving statute, <a href=\"https:\/\/www.ncleg.gov\/EnactedLegislation\/Statutes\/PDF\/BySection\/Chapter_20\/GS_20-138.1.pdf\">N.C.G.S. \u00a7 20-138.1<\/a>.<\/p>\n<div class=\"read_more_link\"><a href=\"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/\"  title=\"Continue Reading The DUI Eye Test (HGN) | What It Measures and How Reliable It Really Is\" class=\"more-link\">Continue Reading<\/a><\/div>\n","protected":false},"excerpt":{"rendered":"<p>The &#8220;DUI eye test&#8221; refers to the Horizontal Gaze Nystagmus, or &#8220;HGN.&#8221; It is one of the three &#8220;verified&#8221; Standardized Field Sobriety Tests (SFSTs) recognized by the National Highway Traffic Safety Administration (NHTSA), along with the walk-and-turn and the one-leg stand. HGN is a &#8220;sobriety test&#8221; where an officer holds a stimulus, usually a pen, [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":574409,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[356],"tags":[703,632,695,699,709,710,698,702,708,424,62,705,696,700,697,711,701,707,683,568,634,712,706,704,713],"class_list":["post-574406","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-dui-dwi","tag-appreciable-impairment","tag-dare-county-dwi","tag-dui-eye-test","tag-dui-field-sobriety-test","tag-dwi-body-camera-evidence","tag-dwi-dash-camera-evidence","tag-dwi-eye-test","tag-dwi-probable-cause","tag-dwi-roadside-testing","tag-field-sobriety-tests","tag-glover-law-firm","tag-hgn-clues","tag-hgn-eye-test","tag-hgn-field-sobriety-test","tag-horizontal-gaze-nystagmus","tag-n-c-g-s--20-138-1","tag-nc-dwi-evidence","tag-nhtsa-hgn","tag-north-carolina-dwi","tag-north-carolina-impaired-driving","tag-outer-banks-dwi","tag-rule-702-hgn","tag-six-clues-hgn","tag-standardized-field-sobriety-tests","tag-state-v-godwin"],"yoast_head":"<!-- This site is optimized with the Yoast SEO plugin v27.4 - https:\/\/yoast.com\/product\/yoast-seo-wordpress\/ -->\n<title>DUI Eye Test | HGN and North Carolina DWI Cases<\/title>\n<meta name=\"description\" content=\"DUI eye test results can affect HGN evidence, probable cause, and DWI cases in North Carolina. Learn how roadside testing is reviewed.\" \/>\n<meta name=\"robots\" content=\"index, follow, max-snippet:-1, max-image-preview:large, max-video-preview:-1\" \/>\n<link rel=\"canonical\" href=\"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/\" \/>\n<meta name=\"twitter:card\" content=\"summary_large_image\" \/>\n<meta name=\"twitter:title\" content=\"DUI Eye Test | HGN and North Carolina DWI Cases\" \/>\n<meta name=\"twitter:description\" content=\"DUI eye test results can affect HGN evidence, probable cause, and DWI cases in North Carolina. Learn how roadside testing is reviewed.\" \/>\n<meta name=\"twitter:image\" content=\"https:\/\/www.dannygloverlawfirm.com\/blog\/wp-content\/uploads\/2026\/05\/DUI-EYE-TEST.webp\" \/>\n<meta name=\"twitter:label1\" content=\"Written by\" \/>\n\t<meta name=\"twitter:data1\" content=\"Danny Glover\" \/>\n\t<meta name=\"twitter:label2\" content=\"Est. reading time\" \/>\n\t<meta name=\"twitter:data2\" content=\"12 minutes\" \/>\n<!-- \/ Yoast SEO plugin. -->","yoast_head_json":{"title":"DUI Eye Test | HGN and North Carolina DWI Cases","description":"DUI eye test results can affect HGN evidence, probable cause, and DWI cases in North Carolina. 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Learn how roadside testing is reviewed.","twitter_image":"https:\/\/www.dannygloverlawfirm.com\/blog\/wp-content\/uploads\/2026\/05\/DUI-EYE-TEST.webp","twitter_misc":{"Written by":"Danny Glover","Est. reading time":"12 minutes"},"schema":{"@context":"https:\/\/schema.org","@graph":[{"@type":"Article","@id":"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/#article","isPartOf":{"@id":"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/"},"author":{"name":"Danny Glover","@id":"https:\/\/www.dannygloverlawfirm.com\/blog\/#\/schema\/person\/ab9e711203dfec3d443c9dd8468ab050"},"headline":"The DUI Eye Test (HGN) | What It Measures and How Reliable It Really Is","datePublished":"2026-05-16T14:00:57+00:00","mainEntityOfPage":{"@id":"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/"},"wordCount":2467,"image":{"@id":"https:\/\/www.dannygloverlawfirm.com\/blog\/dui-eye-test-hgn\/#primaryimage"},"thumbnailUrl":"https:\/\/www.dannygloverlawfirm.com\/blog\/wp-content\/uploads\/2026\/05\/DUI-EYE-TEST.webp","keywords":["Appreciable Impairment","Dare County DWI","DUI Eye Test","DUI Field Sobriety Test","DWI Body Camera Evidence","DWI Dash Camera Evidence","DWI Eye Test","DWI Probable Cause","DWI Roadside Testing","Field Sobriety Tests","glover law firm","HGN Clues","HGN Eye Test","HGN Field Sobriety Test","Horizontal Gaze Nystagmus","N.C.G.S. \u00a7 20-138.1","NC DWI Evidence","NHTSA HGN","North Carolina DWI","North Carolina impaired driving","Outer Banks DWI","Rule 702 HGN","Six Clues HGN","Standardized Field Sobriety Tests","State v. 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