Thirteen people were hospitalized after a crash on Highway 99 in Surrey involving a semi-truck, a bus and multiple vehicles Friday evening, according to police. The Surrey Police Service says the crash occurred just east of the Highway 99 and Highway 91 interchange around 4:30 p.m. The semi-truck and trailer was travelling north and struck three sedans going the same direction, according to police. The truck then left the northbound lanes, jack-knifed and struck the median. It went into southbound traffic and struck a double-decker bus and another sedan. The bus had about 50 to 60 people on board, police added. Paramedics treated 13 people, two of whom were taken to hospital in serious but stable condition, according to police. One was transported to hospital via air ambulance, but has since been discharged. Police say the 11 other people had less serious injuries. The SPS says the cause of the crash remains under investigation, and urged anyone with video to contact them at 604-599-0502 and reference file number 26-111726 (SP.)