The collision involved a city bus, Roberts Hawaii bus, and cement truck and occurred about 7:30 a.m. before the Likelike Highway offramp, according to Honolulu Fire spokesman Capt. Scot Seguirant.
Emergency Medical Services and firefighters responded to the scene.
Paramedics treated eight people — seven passengers and a driver on the city bus — and took them to a hospital in serious but stable condition, according to Honolulu Emergency Services Department spokeswoman Shayne Enright.
Paramedics also evaluated three other people at the scene. They refused transport to a hospital.