Traffic was closed for over two hours Wednesday evening on I-43 southbound at Good Hope Road after a multi-vehicle accident.
The accident took place just after 8:15 p.m. and involved two vehicles.
North Shore Fire and Rescue sharing on social media five people were transported from the scene to Froedtert Hospital for treatment of injuries.
One of them at that time was considered critical, the rest were non life-threatening.
An investigation is underway regarding what caused the accident.