The McMahon Difference Having built an enthusiastic, dedicated team of more than 120 professionals along the East Coast, McMahon Associates, Inc. offers unrivaled breadth and depth in experience in all transportation engineering and planning services. By focusing on relationships, our client support is both attuned to your needs and flexible in addressing your unique concerns. You’ll find in us a trusted advisor in traffic, highways, transit, structures, signals and more, from concept to design and construction services, including helping you find the transportation funding you need to implement your plans.