A large group of teamsters leave the TDIU to form the Teamsters National Union in Chicago.

Teamsters International Union and Team Drivers International combine to form the International Brotherhood of Teamsters.

Teamsters join the strike against Montgomery Ward and the Employers Association of Chicago. The world's first purpose-built gas station is constructed in St. Louis.

Henry Ford installs the first moving assembly line, making mass-produced vehicles viable.

August Charles Fruehauf builds the first "semi-trailer."

Charles H. Martin files a patent for the fifth wheel invented by Herman G. Farr. Arthur Savage patents the radial tire.

Pneumatic tires are developed, enabling trucks to double their speed. The fifth wheel patent is granted to Charles Martin and marketed as the Martin Rocking Fifth Wheel.

The U.S. formally enters World War I. The Goodyear Wingfoot Express succeeds in the first long-distance heavy-duty truck haul using pneumatic tires.

The U.S. military purchases a large number of trucks intended to be deployed in the war effort; World War I formally ends shortly after.

The first air brake system is installed on a road vehicle.

Fruehauf Trailer Co. invents the automatic semi-trailer fifth wheel, in which the coupling and uncoupling was accomplished by one man, using the motion of the trailer itself.

Clessie Lyle Cummins designs a diesel engine suitable for use in trucks.

The first factory-installed diesel engine is accomplished by the Indiana Division of White Motor Trucks.

The American Highway Freight Association and Federation Trucking Associations of America merge in response to the need for uniform industry standards.

The “Code of Fair Competition” for the trucking industry is inaugurated, regulating registration requirements as well as wage and hours controls.

Joseph Numero and Frederick Jones patent the first transport refrigeration unit, making delivery of fresh produce anywhere in the country a possibility.

The Pennsylvania Turnpike officially enters service, exhibiting a new superhighway design and demonstrating that revenue bonds could finance toll roads.

The U.S. formally enters World War II following the attack on Pearl Harbor. Julius Gaussoin invents the 10-speed, single-stick transmission.

Civilian truck production is suspended; manufacturers are repurposed for war production. Fuel and rubber rationing is implemented, and a 35 mph national speed limit is imposed.

Al Gross receives FCC approval to sell CB (citizens band) radios to the general public, allowing for two-way communication between devices.

Fuller Manufacturing commercializes the single-stick 10-speed transmission, known as the "RoadRanger."

Michelin develops the first commercial radial truck tire in Europe.

Cummins and Mack both introduce turbocharged diesel engines.

The Federal Highway Act is signed into law, creating the Interstate Highway System. Malcom McLean launches the world's first intermodal container service.

The engine brake (aka Jake Brake), invented by Clessie Cummins to enable diesel trucks to maintain a controlled speed when descending steep grades, is offered for sale.

The United States Department of Transportation is created.