Final rest of (left) 2020 Peterbilt truck-tractor in combination with 2014 Utility semitrailer; (center) 2018 Mack dump truck, 2

​​​Final rest of (left) 2020 Peterbilt truck-tractor in combination with 2014 Utility semitrailer; (center) 2018 Mack dump truck, 2013 Freightliner truck-tractor in combination with 2017 Utility semitrailer, and 2006 Volkswagen; and (right) 2021 Kia. (Source: Wisconsin State Patrol)

Multivehicle Crash

Investigation Details

What Happened

​​​On June 12, 2020, near the Township of Arlington, Wisconsin, a queue of ​slowed and stopped traffic formed on Interstate 39 because of two previous traffic collisions.1 About 6:45 a.m., a 2013 Freightliner truck-tractor in combination with a 2017 Utility semitrailer struck the end vehicle in the queue, causing a crash involving eight vehicles. Four vehicle occupants died and three were seriously injured.​​


What We Found

​​We determined that the probable cause of the multivehicle crash near the Township of Arlington, Wisconsin, was the truck ​driver’s failure to respond to slow-moving traffic due to fatigue. Contributing to the fatigue was his undiagnosed obstructive sleep apnea.​​​


Lessons Learned

​​Commercial motor vehicle drivers must remain alert and vigilant to changing roadway conditions and traffic hazards. Obstructive sleep apnea is a medical condition that, unless identified and appropriately treated, can significantly reduce a driver’s ability to obtain restorative sleep, leading to fatigue, degraded alertness, and increased crash risk. The National Transportation Safety Board has previously recommended that the Federal Motor Carrier Safety Administration implement a program to identify commercial motor vehicle drivers at high risk for obstructive sleep apnea, and require that those drivers provide evidence through the medical certification process of having been appropriately evaluated and treated before being granted unrestricted medical certification.


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