The Kansas Highway Patrol says six motorcycles crashed on a Topeka highway Monday morning after one of them unexpectedly slowed down. Two of the motorcyclists were injured.

According to the Patrol’s crash report, the line of bikers were traveling along I-70 at Rice Road in Topeka when one of them slowed down for unknown reasons.

“The bike that started to slow down was struck by the motorcycle directly behind it, causing a chain-reaction collision,” according to the report.

The motorcyclists were from far-flung locations across the country, including West Virginia, Indiana, Kentucky, Arizona and Missouri. Two bikers at the end of the line were injured in the crash. James Marshall, 69, of Bruceton Mills, WV., and Clinton Gunter, 65, of Yuma Arizona, were both transported to Stormont Vail Medical Center.