 Early planning efforts between 1978 and 1981 for a new highway reservation from Mundaring to Wooroloo encountered community opposition, and the Environmental Protection Authority (EPA) requested a more detailed environmental assessment.In 1985, a study into the primary east-west traffic routes in the area was commissioned by the Main Roads Department, Metropolitan Region Planning Authority, Shire of Mundaring, and Shire of Swan.It recommended a new alignment, known as the "Orange Route", be selected for the Perth to Adelaide National Highway.