Who We Are Truck Trailer Manufacturers Association (TTMA) is an international trade association whose current membership produces more than 90% of the truck trailers built in the United States. Our Associate Members include more than 100 global material and component suppliers who keep those lines moving. Our efforts engage policies and regulations that play a role in assuring the timely, smooth flow of material to keep production flowing or that affect the cost of production. For almost 75 years the Truck Trailer Manufacturers Association has been here to assist North America's trailer manufacturers. Have questions about Federal Regulations? Need help following the complex code? You can't afford not to be a member.