 Due to a shortage of construction material, the wearing course was executed in various materials—mostly concrete slabs, with some asphalt concrete sections and even some cobblestone-covered sections.The road was originally designed to carry approximately 9,000 vehicles per day, and the original construction plans provided for subsequent conversion of the road into a four-lane motorway.In 1971, as the road gradually became congested, the plans to build the motorway on the route were approved by the Parliament of the Socialist Republic of Croatia.