Police responded to a call of a semi-truck stopped in the median of Interstate 15, near milepost 81 in Fort Hall Saturday night.
According to the Idaho State Police, the driver, Chance Verhelle, 61, stopped the truck because of a medical condition.
Verhelle was unconscious when rescuers arrived.
Both southbound lanes of I-15 were closed while life flight was called in to take Verhelle to Portneuf Medical Center, but the flight was cancelled when Verhelle succumbed to his medical condition.
Verhelle was driven to Portneuf, where he was officially pronounced dead.