Two Inches of Clearance: How I‑5's Span Dropped Into the River

Two Inches of Clearance: How I‑5's Span Dropped Into the River

Seventy-one thousand daily commuters crossed a fracture-critical bridge where an unmarked outer lane offered only 14 feet 7 inches of clearance - and a truck two inches over its permit set into motion a collapse that dropped a 160-foot steel span into the Skagit River. How did a routine permit, decades of inspection reports, and a single lane choice lead to three cars plunging into the water?

In this episode, we lay out the sequence of facts from the May 23, 2013 evening collapse, the bridge’s design vulnerabilities, the truck’s measurements versus its permit, and the inspection history that missed the risk. What small errors and assumptions combined to turn ordinary highway travel into a near‑disaster?

Person: Ed Sherbinski Date: May 23, 2013 Event: 160-foot steel span collapse Location: Skagit River, between Mount Vernon and Burlington, Washington Daily traffic: 71,000 vehicles

- Span length: 160 feet dropped into the Skagit River at 7:00 p.m. on May 23, 2013. - Clearance outer lane: 14 feet 7 inches; inner lane clearance: nearly 17 feet. - Truck permitted height: 15 feet 9 inches; actual truck height recorded: 15 feet 11 inches. - Previous damage: October 2012 strike left a 3-inch gash; inspections in August and November 2012 cleared the bridge. - Fracture-critical count: 18,000 bridges in the United States held the same fracture-critical designation at the time.

To listen to this podcast ad-free and access premium episodes, try our subscription with a 14-day free trial at obomedia.com.

© 2026 OBOMEDIA. All rights reserved. This episode and its content (audio, text, and related materials) are the exclusive property of OBOMEDIA and are protected by applicable copyright laws. Reproduction, distribution, editing, or commercial use, in whole or in part, without prior written permission from OBOMEDIA is prohibited. For permissions, licensing, and business inquiries: [email protected].