All lanes have reopened after a crash on the Waikato Expressway near Mercer. Emergency services responded to a single-vehicle crash on State Highway 1 near Mercer, reported to police just before 2pm. One person has serious injuries, while three have moderate to minor injuries. A Hato Hone St John spokesperson said a patient in a serious condition and two in moderate conditions were taken to Middlemore Hospital. A Fire and Emergency New Zealand spokesperson said crews assisted Hato Hone St John and police. The Serious Crash Unit has been notified.