As executive secretary of the Michigan Road Builders Association, "Irish" Carroll was for 16 years (1948-1964) the leading spokesman of the highway industry in Michigan. Under his leadership, the organization grew in size and stature and gained national recognition, besides achieving a strong working relationship with other segments of the industry, public and private. In that role, and as long-time secretary-treasurer of the Michigan Good Roads Federation, he was a driving force in the enactment of legislation that enabled the State to maintain its highway leadership.