Two of the adults and the foal were “corralled” back into the trailer by 3pm, according to a Washington State Patrol (WSP) spokesman, while the fourth remains on the loose.
Rick Johnson, a WSP trooper, described the incident as “a first for me and all WSP troopers involved”. Writing on social media platform X, he thanked the community for coming together to assist the animals.
A spokesman for the King County Sheriff’s Office told the Seattle Times animal control specialists had attended the scene.
The driver was reportedly transporting the privately owned herd to the neighbouring state of Montana when they broke free.
Laura Fisher, who witnessed the loose zebras when driving down the interstate, told the Seattle Times: “Our main concern was that they were going to jump out of the trailer at 70 [miles per hour] and probably die and cause a major issue for the other drivers.”