The Texas Department of Public Safety says Nelson was not aboard in the weather-related accident around 3:30 a.m. CST Saturday on Interstate 30 near Sulphur Springs, 75 miles northeast of Dallas.
Nelson spokeswoman Elaine Schock says Paul English broke his ankle, his brother Billy English suffered a bruise hip and Tom Harkin has a cracked or bruised rib.
Nelson has postponed his four remaining November tour dates: Robinsonville and Jackson, Miss.; Fayetteville, Ark.; and Lafayette, La.
Trooper Sylvia Jennings says seven people were on the westbound bus, including the driver who was dealing with wet roads and high winds.