Throughout 2013, Pressure Systems International (P.S.I.) is celebrating its 20th anniversary of providing automatic tire inflation systems for commercial vehicles by honoring twelve fleets, three for each five year interval from 1993 through the present, that have played a major role in the success of the company. On June 10, Frank Sonzala and Mike Niemeyer presented the sixth in the series, the June Fleet of the Month award, to U.S. Express at their Chattanooga headquarters. Each of the fleets honored in the first half of 2013 were instrumental in building the company’s foundation:
- January – H-E-B, one of the largest independent food retailers in the nation headquartered in San Antonio, TX started testing and using P.S.I.'s automatic tire inflation system for commercial vehicles in 1994, playing a major advisory role in advancing and improving the original design.
- February - Landstar was honored for having the first OEM installation at Great Dane Trailers in Savannah, GA 1996.
- March - Union Pacific Railroad, the first Intermodal customer to embrace P.S.I.'s automatic tire inflation system with a chassis order of 3000 units in 1997.
- April – P.A.M. Transport, the first major fleet to do an in-depth study of tire wear and maintenance costs when the then vice president of maintenance, Carl Tapp, tested P.S.I's system on 200 trailers. His findings proved that tire wear, and tread life increased, tires wore better and that roadside service calls associated with tires could be eliminated.
- May – Averitt Express, honored during P.S.l.'s Annual Fleet Technology Event. Averitt’s adoption of the P.S.I. automatic tire inflation system after considerable testing proved to be a pivotal time for the new product to become the option of choice among larger carriers.
- June – U.S. Express undertook the first significant retro-fit of the P.S.I. automatic tire inflation system to older trailers to determine if it would benefit their fleet. It proved itself and is now standard on all new U.S. Express trailers.