John A. Nicholson formed the Nicholson Company in 1953. Nicholson Company became the first air-cooled Deutz diesel engine distributor in the United States.

In the '70s, the Nicholson Company began designing and building various levers, controls and cables, giving birth to ADDCO's Industrial Products Group.

The '80s found ADDCO looking for new applications for the Deutz engine. This led to using the Deutz engine to power the DOT-SIGN®, the first flip disk, portable, changeable message sign. This prompted entry into the traffic control industry. The Traffic Control Group was born.

In the '90s, ADDCO developed innovations such as the Energy Manager software for control of diesel engines, the Solar Tilt And Rotate (STAR), the Eclipse System for enhanced sign legibility, and The BRICK® modular message sign system. ADDCO also developed the first radio-linked portable traffic signal, the PTS-2000. The Smart Zone® was introduced; and the ERC (Electric Remote Control) was developed.